Free Forensic Tips

Patterns in the relationship between mental disorder and crime

2009-06-16T12:26:00.004+05:30

Numerous studies conducted with offender or forensic psychiatric samples have revealed that individuals with psychopathic traits are at risk for violence and other externalizing psychopathology. These traits appear to be continuously distributed in these offenders, leading investigators to speculate on the presence of such traits in the general population.Five patterns among mentally disordered offenders are distinguished by the relationship between mental disorder, on the one hand, and criminality, on the other. ( Picture courtesy: harfordmedlegal.typepad)

· Pattern 1 offenders are those for whom crime is a response to psychotic symptoms, most often delusions or hallucinations.·

Pattern 2 offenders commit crimes motivated by compulsive desires, such as sex offenses by paraphiles and offenses regarded as evidence of disorders of impulse control.·

Pattern 3 offenders are those with personality disorder for whom the crime is merely one example of a maladaptive pattern of voluntary and knowing behaviour.·

Pattern 4 offenders have coincidental mental illness that is unrelated to the crime.·

Pattern 5 offenders are those who become mentally disordered or feign mental disorder as a result of their crimes, such as those who dissociate upon seeing what they have done, those who become depressed in prison, those who become psychotic on death row, and those who malinger mental illness.
(Int J Law Psychiatry)

Although these categories do not determine whether offenders are responsible for their behaviour, some unknown proportion of Pattern 1 offenders do meet legal criteria for insanity, depending on the facts of each case and the applicable legal standards. It is arguable whether or not Pattern 2 offenders ever meet legal criteria of insanity. Offenders evidencing only Patterns 3, 4, or 5 are not candidates for an insanity defence.

There is therefore a need for researchers and policy makers in the area of mental health and law to collaborate and develop common methods of approach to research. Despite the knowledge of prevalence of mentally ill offenders in jails and prisons, there are a number of research questions that remain. The relationship between substance abuse and mental disorders has also been a topic not very well researched. It is significant because a lot of substance abuse offenders, also happen to be mentally ill offenders.

FORENSIC APPLICATION OF CHEMISTRY IN TOXICOLOGY

2009-06-10T10:20:00.006+05:30

• Identify illicit drugs.

• Analyse drugs and poisons in human tissue and body fluids; including blood alcohol determinations.

• Examine and compare materials such as fibres, paints, cosmetics, oils, petrol, plastics, metals, soils and gunshot residues.

• Examine items of human and animal biological material to be compared with victims and suspects using DNA profiling.

• Conduct botanical identification of plant materials at trace levels, and whole-plant identifications.

There are many areas in forensic chemistry, but this report focuses on three main areas, which are of the greatest relevance to forensic chemistry. They are: Trace Analysis, Toxicology and Serology. The analytical techniques involved in forensic analysis are shown in the flowchart attached to Appendix 1 of this report TRACE ANALYSIS. The trace analysis applications in forensic chemistry include the analysis of many substances such as gunshot and primer residue, paint, hair, and fibres. This substance range from being microscopic to macroscopic in size. Paint Analysis Paint analysis is especially useful in hit-and-run cases, where paint is usually left at the scene of a crime. The paint is first analysed by Gas Chromatography and then by a Scanning Electron Microscope. The first method is used for comparing the organic binder in the paint with that of a standard (for example, paint from a suspect's vehicle), and the scanning electron microscope is used for identifying the constituents of the inorganic pigments present in the paint. Hair and Fibre Analysis Hair and fibre analysis is usually performed by comparison microscope work, where a known standard is physically compared to the evidence. A polarizing microscope is especially useful for fibre analysis to help identify the class of fibre under inspection. Arson Analysis Forensic arson analysis deals with the analysis of fire debris for the presence of accelerants. Some common accelerants found in arson cases are petrol, diesel, and lighter fluid. Fire debris submitted for arson analysis is packaged in sealed containers, such as mason jars, that are sterile to prevent contamination of the sample. The chemist performs the analysis by inserting activated charcoal (C-strips) into the "headspace" of the sealed container. The C-strip is subsequently removed from the container and placed in carbon disulfide. The accelerants desorb from the C-strip and dissolve into the solvent. This solution is then injected into a Gas Chromatograph. Gas Chromatography Gas Chromatography is the most sensitive of all the chromatographic techniques. It is capable of measuring as little as 10-12grams of a compound. Once a sample is ready to be analysed, it is placed into the injection port of the gas chromatograph. The injection port is heated to a temperature that is sufficient to instantly vaporise the sample. The vaporised sample is then swept into a column by a carrier gas. The carrier gas is usually nitrogen; it is often used because it is an inert gas and will not react with the sample and cause error. The column consists of a series of glass coils, which are only about 4mm in diameter. These coils are packed with a porous solid that has been coated with a high-boiling liquid hydrocarbon. The liquid acts as a liquid stationary phase. The components of the sample repeatedly pass into and out of solution with the stationary phase. The least soluble components are swept out of the column first by the carrier gas, into the detector. The detector calculates the time it takes for separate components to pass through the column. By knowing the time it takes, and the amounts of the substances present, a graph can be drawn and the constituents of a sample calculated.

Forensic toxicology deals with qualitative and quantitative analysis of biological specimens for the presence of alcohol, drugs, and/or poisons and their corresponding metabolites. Investigations often involve driving-under-the-influence of alcohol.

Drug Analysis

The major area in toxicology is drug analysis, which deals with the identification of illicit drugs. Because of the increased popularity of cocaine, the majority of drug analysis cases involve cocaine analysis, along with other spot tests for the detection of opiates (such as heroin and morphine), amphetamines, barbiturates, marijuana and lysergic acid diethylamide (LSD). Gas Chromatography and Mass Spectroscopy are the most often used laboratory techniques for drug identification. Mass Spectroscopy Combined with a gas chromatograph, a mass spectrometer is probably the most powerful tool available to a forensic chemist dealing with drug analysis. Mass spectrometry is a powerful analytical technique that is used to identify unknown compounds, to quantify known compounds, and to elucidate the structure and chemical properties of molecules. Detection of compounds can be accomplished with very minute quantities (as little as 10-12mg). This means that compounds can be identified at very low concentrations in chemically complex mixtures. When samples such as blood are to be analysed for drug content, the sample is first vaporized and then injected into the main body of a mass spectrometer. The gaseous sample is then admitted through a small inlet into an ionisation chamber. Here the sample is bombarded with electrons, forming ions with a single positive charge. The positive ions are accelerated to high speeds by an electric field until they enter a region where there is a perpendicular magnetic field. This field causes the ions to move in curved paths, with a radius dependant on the mass to charge ratio of the ions. Only ions with a particular radius will reach the collector. By changing the accelerating voltage or the strength of the magnetic field, ions of different masses can reach the collector. The collector measures the current due to the different ions and the data is recorded as a mass spectrum. It is in these mass spectrums that chemicals such as drugs can be identified. The mass spectrum of cocaine demonstrates how a forensic laboratory might determine the nature of an unknown street drug.

Forensic serology deals with the study of body fluids that might have probative value in the prosecution of a crime. Typical fluids are blood, semen, and saliva. After testing to identify these substances, it is possible to begin to identify the donor of the material by testing for "blood group substances" (from the ABO blood group system) or other proteins that are polymorphic. DNA Analysis Forensic DNA analysis deals with the identification of the source of a body fluid through DNA testing. Fluids, which are often left at the scene of a crime, which contain DNA, are blood, semen and saliva. The chemical structure of everyone's DNA is the same. The only difference between individuals is the order of the base pairs, which make up the structure of DNA. A newly developed technique called “DNA fingerprinting” utilises these different base pair sequences to identify an individual. DNA Fingerprinting DNA fingerprinting has established itself as an efficient and highly accurate means of determining identities and relationships. It has practically revolutionized the field of forensics, especially concerning rape cases. DNA fingerprinting is achieved by using the laboratory technique known as gel electrophoresis.

Gel electrophoresis is the best method for the separation and qualitative analysis of very large molecules that have an overall charge. It is similar in many ways to chromatography. The process of electrophoresis for DNA fingerprinting is summarised below.

1. DNA is extracted from blood, semen, hair roots or other body tissues.
2. Strands of DNA are cut into fragments using a restriction enzyme.
3. The DNA fragments are separated into bands during electrophoresis.
4. The DNA band pattern is transferred to a nylon membrane.
5. A radioactive “probe” binds to bands on the membrane.
6. X-ray film is placed next to the membrane to detect the radioactive pattern.

The film is developed to create a permanent “fingerprint suitable for examination.”

With the laboratory techniques listed so far in this report, plus many others, forensic chemists are able to determine what happened at the scene of a crime. They have the power and authority to identify a criminal, and just as importantly, clear an innocent suspect. Forensic chemistry is always improving as new advances in technology take place. Research in this field is focused upon finding new ways of analysing collected evidence that are cost effective and give fast and precise results.
This report outlines the significance chemistry has in criminal investigations. Three major areas of forensic chemistry are outlined including: Trace Analysis, Toxicology and Serology. Methods of analysis such as Gas Chromatography, Mass Spectroscopy and Electrophoresis are also summarised.

Chromatography

Chromatography is a method of separating substances that make up a liquid or gaseous mixture. One use of it is to measure or identify low concentrations of substances, such as pollutants in air or water. Another use is to separate and identify products of chemical reactions. Chemists use this method to separate pure substances from impurities. Chromatographic methods are based mainly on a process called adsorption. A mixture passes through a solid or liquid material that adsorbs to substances. This material is called an adsorbent. A liquid or gas added to the mixture helps move it through an adsorbent. Various substances are adsorbed at different rates of speed, so the substances in a mixture separate from one another as the mixture moves through the material. Common chromatographic methods are liquid column, thin layer, and gas chromatography. Liquid Chromatography For compounds that cannot be volatilized readily, the liquid chromatograph can be used instead of the gas chromatograph. The stationary phase consists of a finely powdered solid adsorbent packed into a thin metal column and the mobile phase is made of an eluting solvent forced through the column by a high-pressure pump. The mixture that needs be analyzed is injected into the column and monitored by a detector. Many different liquid chromatograph packing and eluting solvents are available to achieve the desired resolution. Thin-Layer and Paper Chromatography. A layer of adsorbent also can be spread on a glass plate, instead of packed into a column, for analytical purposes. By means of a thin capillary tube, the plate is spotted with a solution of the mixture that is to be resolved, and the solvent is allowed to evaporate. An eluting solvent is then allowed to move up the plate by capillary action, drawing the components of the mixture along by varying degrees. Spraying it with an oxidizing agent develops the plate, so that each component becomes charred and appears as a dark spot on the plate. The location and size of the spots serve to identify and measure the relative quantities of the components. As in column chromatography, polar substances will not elute as well and will remain nearer the bottom of the plate, while non-polar substances will elute to the top. This process is called thin-layer chromatography. In paper chromatography a procedure similar to thin-layer chromatography is used except that the cellulose in the paper acts as the adsorbent. The gas chromatograph is a system consisting of a liquid with a high boiling point impregnated on an inert solid support as the stationary phase and helium gas as the mobile phase. The stationary phase is packed into a thin metal column and helium gas is allowed to flow through it. The column is attached to an injection port, and the entire system is heated in an oven. A solution of the mixture is injected into the column through the injection port by means of a syringe and is immediately volatilized. The helium gas then sweeps the components out of the column and past a detector. The polarity of the compounds and their volatility determines how long the column retains them. When each component passes the detector, a peak is registered on a recorder. The relative quantities of the components can be determined from the relative areas under the peaks. By varying the polarity of the column and its temperature, many different resolutions can be carried out. Since the capacity of gas chromatograph columns is very low, the gas chromatograph is used chiefly as an analytical tool, although it can be used for preparative purposes as well. Miniaturized gas chromatograph instruments have been employed in space probes to analyse the atmospheres of other plane.

So how does a mass spectrometer work? Mass spectrometers can be divided into three fundamental parts, namely the ionisation source, the analyser, and the detector. The sample under investigation has to be introduced into the ionisation source of the instrument. Once inside the ionisation source the sample molecules are ionised, because ions are easier to manipulate than neutral molecules. These ions are extracted into the analyser region of the mass spectrometer where they are separated according to their mass (m) -to-charge (z) ratios (m/z). The separated ions are detected and this signal sent to a data system where the m/z ratios are stored together with their relative abundance for presentation in the format of a m/z spectrum. The analyser and detector of the mass spectrometer, and often the ionisation source too, are maintained under high vacuum to give the ions a reasonable chance of travelling from one end of the instrument to the other without any hindrance from air molecules. The entire operation of the mass spectrometer, and often the sample introduction process also, is under complete data system control on modern mass spectrometers. The method of sample introduction to the ionisation source often depends on the ionisation method being used, as well as the type and complexity of the sample. The sample can be inserted directly into the ionisation source, or can undergo some type of chromatography en route to the ionisation source. This latter method of sample introduction usually involves the mass spectrometer being coupled directly to a high pressure liquid chromatography (HPLC), gas chromatography (GC) or capillary electrophoresis (CE) separation column, and hence the sample is separated into a series of components which then enter the mass spectrometer sequentially for individual analysis. Many ionisation methods are available and each has its own advantages and disadvantages. The ionisation method to be used should depend on the type of sample under investigation and the mass spectrometer available. Ionisation methods include the following: Atmospheric Pressure Chemical Ionisation (APCI) Chemical Ionisation (CI) Electron Impact (EI) Electrospray Ionisation (ESI) Fast Atom Bombardment (FAB) Field Desorption / Field Ionisation (FD/FI) Matrix Assisted Laser Desorption Ionisation (MALDI) Thermospray Ionisation (TSP). The ionisation methods used for the majority of biochemical analyses are Electrospray Ionisation (ESI) and Matrix Assisted Laser Desorption Ionisation (MALDI). With most ionisation methods there is the possibility of creating both positively and negatively charged sample ions, depending on the proton affinity of the sample. Before embarking on an analysis the user must decide whether to detect the positively or negatively charged ions separation of Sample Ions. The main function of the mass analyser is to separate or resolve the ions formed in the ionisation source of the mass spectrometer according to their mass-to-charge (m/z) ratios. Various mass analysers have different features, including the m/z range that can be covered, the mass accuracy, and the achievable resolution. The compatibility of different analysers with different ionisation methods varies. For example, all of the analysers can be used in conjunction with electro-spray ionisation, whereas MALDI is not usually coupled to a quadruple analyser.

Example of a GC-MS Instrument (Picture Courtesy: forensic.iupui.edu)

Tandem (GS-MS) mass spectrometers are instruments that have more than one analyser and so can be used for structural and sequencing studies. Analysers do not necessarily have to be of the same type, in which case the instrument is a hybrid one.

The detector monitors the ion current, amplifies it and the signal is then transmitted to the data system where it is recorded in the form of mass spectra. The m/z values of the ions are plotted against their intensities to show the number of components in the sample, the molecular weight of each component, and the relative abundance of the various components in the sample. The type of detector is supplied to suit the type of analyser; the more common ones are the photomultiplier, the electron multiplier and the micro-channel plate detectors.

Drug Identification with Gas Chromatography Mass Spectrometry

Drug Identification with Gas Chromatography Mass Spectrometry Drugs is used everyday by people in many different ways for many different reasons. Drug testing has become a standard in pre-employment testing because of the wide variety of drugs used in society nowadays. Drugs tested for by a possible employer include Cocaine, Amphetamines, Opiates (codeine, morphine, and heroin), PCP (phencyclidine), and Marijuana. Gas chromatography/mass spectrometry is used to test hair and urine samples of possible drug abusers or job applicants, and it is the best method for the testing of drug use. Gas chromatography and mass spectrometry are two different methods for identifying chemical substances, and the two instruments have be coupled together to perform a highly complementary analytical function. The gas chromatograph and the mass spectrometer have theories behind how their techniques work, and specific forensic applications for their instrumentation. The gas chromatograph offers rapid and very high-resolution separations of a very wide range of compounds, with the only restriction that the analyzed substance needs to have sufficient volatility. The theory behind the mass spectrometer is to use the difference in mass-to-charge ratio (m/e) of ionized atoms or molecules to separate them from each other. Mass spectrometry is therefore useful for quantitation of atoms or molecules and also for determining chemical and structural information about molecules. Molecules have distinctive fragmentation patterns that provide structural information to identify structural components. The combination of the gas chromatograph and mass spectrometer is very easy, because both instrument needs to be modified in excess and both are analyzed in the gas phase and have comparable sample levels and temperature ranges. The most important feature of the two instruments being coupled is that they perform complementary analytical functions. The instrument’s parts include an injector, a carrier gas, a column, a separator, an ionization source, mass separator, and an ion detector. The injector is located on the gas chromatograph and is where the sample gas is injected into the instrument to start the process. The sample gas is then mixed with a carrier gas, which is the mobile phase in gas chromatography. The mixture proceeds into the capillary column where the separation of the sample begins. The capillary column is 15 to 60 meters in length and .25 to .75 millimetres in diameter. Once through the capillary column the now separated sample enters the separator. The separator connects the gas chromatograph with the mass spectrometer, and separates the carrier gas from the separated components of the mixture. The sample now enters the mass spectrometer’s ionization source where the sample molecules are fragmented and created into positively charged ions by high beam electrons. The fragmented positively charged ions now pass through the mass separator, which is a magnetic field. The mass separator isolates the fragmented sample into their masses. The isolated masses are read by an ion detector and then displayed as a mass chromatogram. A mass chromatograph is a graph of ion m/e abundance in relation to time. The gas chromatograph/mass spectrometer (GC/MS) produces a mass chromatogram of a substance that acts like a fingerprint for a chemical substance. The idea that a GC/MS produces a fingerprint for a chemical substance makes this instrument a convenient option when testing for drug identification and testing people for drug abuse. Forensic scientists find a drug’s identification by using a GC/MS, and use the mass chromatogram in comparison with the test results of another unknown mass chromatogram. If the two mass chromatograms match then the tested chemical substance is that drug it was matched against. Another application is using a GC/MS, and thereby testing hair or urine samples of people to determine if the subject to drug abuse. Drugs tested for might encompass such well-known drugs as Cocaine, Amphetamines, Opiates (codeine, morphine, heroin), PCP (phencyclidine), and Marijuana.

Gas chromatography/mass spectrometry is now considered the premier technique for separations and analysis of drugs. Employers will often test prospective employees for drug use. They test with the hair or urine samples of the prospective employee and run the sample through a GC/MS to determine if the possible employee has used drugs. They determine this by comparing mass chromatograms of known drugs with that of the test sample. The gas chromatograph/mass spectrometer is known as the best resource to prove the identification of a substance of abuse, because the mass chromatographs act like a fingerprint of a chemical.

Terror Strikes Cricket

2009-03-03T20:12:00.002+05:30

I do not know how to react except to say that unfortunately I am not surprised by what happened today in Pakistan. I am assuming that Pakistan will be blacklisted by one and all. They will be the biggest losers.

Guidelines Regarding Medico-Legal Case

2009-03-01T20:34:00.005+05:30

What is a Medico-Legal case?

Communication of facts observed by Medical Officer, during examination and/or treatment of a person, to law enforcing agencies, in relation to criminal offences is called a Medico-legal case. The Doctor is under a legal obligation to give such information and failure to do so will attract legal penalty.

Treatment First, Documentation Later:

Doctor should not be so much apprehensive about medico-legal case, to the extent that he forgets to take immediate life saving measures. His prime duty is to treat a patient. This point has been repeatedly emphasized by Governments and Courts around the world that "doctors should immediately treat the patient without waiting for police formalities, which can be done later, after the treatment has begun." Failure to do so may hold the doctor responsible for medical negligence. The treatment has to take precedence over medico-legal documentation.

Types of cases to be registered as Medico-Legal:

Following categories of cases admitted or attended are to be treated as M.LC.:

• All the cases of accident , burns (specially females within seven years of their marriage), poisoning, drowning, hanging, intoxication, electric shock, lightening or physical death where a foul play is suspected.
• All accident cases where the patient is grievously injured or is likely to die.
• Sexual Assault.
• Criminal Abortions
• All unconscious cases where the cause of unconsciousness is not clear.
• All brought dead cases where there is suspicion of foul play.
• Cases referred from a legal court of law.

Responsibility of Medical Officer who makes the M.L.C.:

The above list is not comprehensive. The attending doctor has to base his judgment, depending on the circumstances and nature of the injury or illness and if he has suspicion that some foul play is involved, he should go ahead with the registration of the case as M.L.C.
The doctor should not obtain any declaration from the patient or his attendant regarding his refusal for M.L.C. It shall be the prime responsibility of the Casualty Duty Officer attending to a case whether to label it as M.L.C. or not.

Consent in Medico-Legal Cases:

Consent for Medico-legal examination, in writing, be taken from all cases, except those brought by police, being arrested on charge of committing an offence. If the person is below 12 years of age, the consent of the guardian should be taken.

Forensic DNA applications

2009-01-16T14:26:00.002+05:30

When you hear about police solving a crime you will often hear that they were able to “crack the case wide open” with the help of a DNA testing method. DNA testing methods are associated with solving crimes in many different cases including rapes and violent crimes, property crimes, missing people, and more.

What most people don’t know is that there are different DNA testing methods that may be employed based on the amount of material present and the information that needs to be derived from the testing. (Picture: Analtech.com)

DNA Testing Methods Used to Solve Crimes:

When it comes to solving a crime and forensic scientist will generally look at the case and determine whether they should use Restriction Fragment Length Polymorphism (RFLP) or Polymerase Chain Reaction (PCR) DNA testing. These are two standardized types of tests and one is better for some situations than others.

For instance, if there is only a very little amount of DNA a forensic scientist isn’t going to elect to use RFLP DNA testing because this type of testing requires large amounts of testing material. On the other hand, if there is an old case and the DNA has degenerated over time RFLP may be the best option. PCR tests are often the test of choice because they are faster and easier than RFLP tests. Of course, there are other testing options, too.

RFLP is a much more accurate than PCR, unfortunately RFLP has been almost completely replaced by PCR. PCR is short for polymerase chain reaction and it is a reference to many different tests. This type of testing is very susceptible to errors in collection and testing practices, therefore tests with erroneous results are not uncommon. These tests simply increase the amount of DNA so there is more of it for typing.

A more common type of DNA test done today is the STR or Short Tandem Repeats. This is a type of test that looks for short repeating DNA sequences. The test is done to distinguish the repeating characteristics of one person’s DNA to another to determine if DNA is the same as a sample or different.

In addition to this typing method there are also polymarkers, and DQ alpha locus. Each test can be used independent of the others or in conjunction with the others as the forensic scientist sees fit.

A forensic scientist will be able to solve crimes using these testing methods because with them they can copy and amplify DNA samples that they have and then easily compare and contrast them to a suspects DNA.

This can help to identify missing people that are found, murder victims, and even get DNA from the fingerprints of someone who has broken into a property or committed a crime.

A forensic scientist has all of these testing options at their disposal, which can help eliminate the possible suspects or individuals to a very limited and improbable number of people, effectively convicting or identifying someone based on the science of DNA alone.

Preservation of Viscera for Analytical Toxicology

2008-12-28T20:50:00.003+05:30

Following death there can be rapid changes in cellular biochemistry as autolysis proceeds, and drugs and other poisons may be released from their binding sites in tissues and major organs, also unabsorbed drug may diffuse from the stomach. Special care should always be taken in the selection of blood and tissue sampling site(s), the method of collection of samples, and the labelling of sample containers. (Image courtesy: rimkus.com)

There is substantial published evidence to show that for most drugs and poisons, including alcohol, there are important differences in their concentration in blood according to the time of specimen collection after death, choice of sampling site, method of sampling and volume of blood collected (Pounder and Jones 1990; Pounder 1993)

Blood for quantitative analysis
Blood for quantitative analysis (~ 5mL) should be obtained from two distinct peripheral sites, preferably left and right femoral veins, taken with care so as not to draw a large volume containing blood from more central vessels. The precise sampling site must be indicated on the label. Femoral blood can be taken by cutting the external iliac vein proximal to the inguinal ligament and milking the distal cut end into a plain 20mL sterile plastic container. Approximately 5mL of this blood should be placed in a fluoride/ oxalate tube containing 1% (w/v) sodium fluoride as a preservative.

Blood for qualitative analysis (screening)
An additional larger specimen of blood (~ 20mL) for qualitative screening should be taken from the heart (preferably right atrium or inferior vena cava) or if necessary from another convenient large vessel. This specimen should be placed in a plain 20mL sterile plastic container. The site of collection must be indicated on the label.

All organs to be preserved should be placed in separate sample containers to remove any chance of cross-contamination. Preservatives such as formalin must never be used. Sample containers should be clearly labelled.

Stomach tissue and contents
These materials may be useful in the investigation of oral cyanide poisoning, or in cases of rapid death where relatively large amounts of unabsorbed drug may be found in the stomach. In cases of suspected drug overdosage the entire stomach contents should be retained. If distinct tablets or capsules are observed in the stomach contents, these should be carefully extracted, and put in individual containers (e.g. plastic urine containers).

Liver
This tissue may be useful in certain complex poisoning cases. It is usual to take a portion of the right lobe of liver since it should be uncontaminated with bile and less affected by drug diffusion from the stomach; 100 grams are sufficient for most analytical purposes.

Brain
A portion of about 100g brain may be useful in the investigation of death due to gases or volatile substances (e.g. butane). The specimen should be placed in a glass specimen jar or nylon bag and deep-frozen prior to transport to the laboratory.

Lung
A portion of about 100g lung from the apex may be useful in the investigation of death due to gases or volatile substances. The specimen should be placed in a glass specimen jar or nylon bag and stored at 4oC prior to transport to the Laboratory.

Hair
Hair specimens may be useful in the investigation of death related to drug abuse (particularly opiates and methadone). Analysis of hair (approximate rate of growth 1 cm per month) is able to provide useful information concerning the chronicity of drug abuse, which is valuable in the interpretation of post mortem drug concentrations. If hair specimens are cut from the head, the proximal end should be clearly identified; the cut end tied with a piece of thread. However, the Laboratory does not currently provide a hair analysis service.

Vitreous Humour
A sample of vitreous humour is useful where a body has been exposed to heat, or if putrefaction is beginning to occur. This specimen may be especially useful for certain biochemical tests such as urea, creatinine, glucose, lactate and electrolytes; in addition to analysis of alcohols and heroin. More information on the collection of vitreous humour can be found in the recent reviews of Forrest (1993) and Knight (1995, 2002).

Nails and Bone
These specimens may be useful in the investigation of certain types of chronic metal poisoning, notably arsenic and lead.

DOCUMENTATION
The following documentation is desirable in every case:
· Details of the deceased, including name, age and date of birth.
· Relevant medical history, particularly with regard to prescribed medication and whether the deceased suffered from a serious infectious disease such as hepatitis, tuberculosis or AIDS.
· Circumstances surrounding the death, including date/time of death if known (particularly regarding deaths in hospital).
· Details of the name and quantity of the substance(s) thought to have caused death.
· A copy of the Pathologist's preliminary report indicating the likely cause of death.
· Details of the type of specimens obtained and the specific site of collection.
· Name, address and telephone number of the Pathologist and Coroner's Officer involved in the case.
· State HM Coroner's District and name, address and telephone number of HM Coroner (for billing purposes).
All of the above information is required to enable the Laboratory to provide an accurate interpretation of results and an efficient service.

Source: toxlab.co.uk

Insects Tell A Tale

2008-12-25T21:08:00.003+05:30

Forensic Entomology, or Medico-criminal Entomology, is the science of using insect evidence to uncover circumstances of interest to the law, often related to a crime. The time of death, for example, can usually be determined using insect evidence gathered from and around a corpse, provided the evidence is properly collected, preserved and analyzed by an appropriately educated forensic entomologist.

Insect scientists, or entomologists, are being called upon with increasing frequency to apply their knowledge and expertise to criminal and civil proceedings. They are also recognized members of forensic laboratories and medical/legal investigation teams.

Forensic entomology proceeds on the common observation that exposed remains present a temporary and progressively changing habitat and food source for a wide variety of organisms ranging from microbes like bacteria and fungi to vertebrate scavengers.

Out of these, arthropod fauna comprises a major element of the biota and insects form the most constant, diverse and conspicuous group. These six- legged creatures pre-dominate the terrestrial and fresh water carrion fauna (Payne, 1965). Cadavers are often fiercely contested by great number of insect species. The overwhelming majority are flies and beetles.

The flies and beetles achieve their success in this transient habitat through quite different sets of pre-adaptations. The dipterans typically have short lived and very mobile adults which are able to search for the suitable habitat over a large area in a short time. The coleopterans are less mobile as adults, but longer lived, and are able to search for much longer time, so that a comparable area can be covered. Coleopteran larvae tend to develop at a slower rate than their dipteran counterparts, but their mouthparts are better adaptable to different kinds of food: an advantage in the rapidly changing conditions within the carrion (Tantawi et al., 1996).

The science of forensic entomology is based on the analysis of those insects which sequentially colonize a corpse as decomposition progresses and on the rate at which the various stages of their progeny develop. This entomological information can be useful during criminal investigations in order to determine the following:

· Time Since Death: There are two basic approaches to the application of entomological data for estimating the time of death. During earlier stages of decomposition, the time elapsed since death or postmortem interval (PMI) may be determined by calculating the time required for a given species to reach the particular stage of development recovered from the corpse at the time of discovery.

· Mode Of Death: A dead body having external injuries is more attractive to insects than one having none. So, depending upon the degree of degradation brought about by maggots, an entomologist may be able to suggest the possible mode of death, e.g. strangulation or mutilation (Anderson, 1997). Another application is in the cases where death has occurred due to intake of drugs. A chemical analysis of the maggots found on the dead body can reveal the specific drugs, especially helpful when no human tissues are available for sending to the laboratory for other tests.
· Place Of Death: The deceased may have been killed at a place other than where the body is found. With knowledge about the carrion fauna of an area and specific habits of species found on the cadaver, an entomologist can help to determine whether the person died at a place other than where the body has been found. Similarly, route of transport of a dead body may also be traced by using entomological data.

Tracing a Firearm: Clues from the bullet

2008-12-24T07:35:00.003+05:30

While a firearm is not usually left at the scene of a crime, a bullet quite often is found at the crime scene (if not in the victim!). There are a number of techniques and tools to identify a bullet from a specific firearm. A bullet should be carefully collected to initially compare it to a certain firearm. Then, a forensics expert investigates to see if the bullet coincides with the calibre of the firearm in question. The bullet is then analysed to see if the rifling impressions pattern is the same pattern of rifling in the barrel of the firearm being investigated. Assuming the two match up on these aspects, forensic scientists would then attempt to match unique, individual characteristics that can transfer from the firearm barrel to the bullet.
The transferred characteristics look a bit like a bar code, due to the pattern of striations and scratches. Inside the gun barrel, there are imperfections that cause striations on the projectiles. If you picture the bullet moving down through the barrel of the gun, unique striations are left on the bullet due to those imperfections on the surface inside the gun. Forensic scientists can look at these patterns through various forensic science procedures.
If police can find a potential weapon used in a crime, forensic experts can then analyse the striations on the bullet, which occurred during its passage through the gun. This allows forensic scientists to run test bullets through the gun to compare the resulting marks with the recovered bullets. In cases where the bullet is too mangled to observe striations or no gun is recovered, police would have to employ other strategies for linking up a suspect with a crime.

Post Traumatic Stress Disorder

2008-12-17T21:51:00.003+05:30

Post-traumatic stress disorder is a type of anxiety disorder. It can occur after you've seen or experienced a traumatic event that involved the threat of injury or death. (Picture Courtesy: NIGMS
Post-traumatic stress disorder (PTSD) may occur soon after a major trauma, or it can be delayed for more than 6 months after the event. Age is not a factor. Everybody is susceptible. It commonly follows natural disasters, events like war, assault, domestic abuse, rape etc. Though these efforts can cause stress to anybody, not all develop PTSD.
It is not known what causes PTSD. Psychological, genetic, physical, and social factors are involved.
Symptoms: Flashback episodes, Feelings of detachment, Inability to remember important aspects of the trauma, Difficulty concentrating, hyper vigilance, outbursts of anger, Sleeping difficulties, survivor guilt etc.
A number of factors have been linked to recovery from trauma. In addition, treatments are available that have been found to help people recover from PTSD. Medication has also been found to help individuals with PTSD better cope with their symptoms.
Treatment aims to reduce symptoms by encouraging you to recall the event, express your feelings, and gain some sense of control over the experience. In some cases, expressing grief helps to complete the necessary mourning process. Support groups, where people who have had similar experiences can share their feelings, are very helpful.
People with PTSD may need to treat depression, alcohol or substance abuse, or related medical conditions before addressing symptoms of PTSD. Behavioral therapy is used to treat avoidance symptoms. This can include being exposed to the object that triggers your symptoms until you become used to it and no longer avoid it (called graded exposure and flooding).
Medicines that act on the nervous system can help reduce anxiety and other symptoms of PTSD. Antidepressants, including selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, can be effective in treating PTSD. A doctor should monitor you if you take these drugs, because they have side effects. Sedatives can help with sleep disturbance. Anti-anxiety medicines may be useful, but some types, such as benzodiazepines, can be addictive.

Rape Victim; Collection of evidence and follow up

2008-12-16T20:57:00.004+05:30

Most of the evidence for prosecution of a sexual assault is medical evidence obtained from the victim. It is most important that the victim gets medical treatment as soon as possible and does not bathe, shower, douche, or change clothes until given permission by medical personnel. If possible, it is also very helpful if the victim refrains from using the bathroom.

Collection of evidence: In most setups, the medical examination is carried out by a nurse trained in collection of forensic evidence. There are countries where the same is done by Gynecologists. Whoever does it (Depending on the local setup), the protocol is standard.
1. Detailed medical history to rule out any existing medical conditions before beginning medical examination.
2. The nurse explains the hospital's HIV testing procedure and why HIV testing is beneficial. The victim then decides whether or not to permit HIV testing.
3. Routine blood collection for pregnancy check, ruling out other social diseases.
4. General Examination- documentation of evidence of torn clothing or external injuries and collecting photographic evidence. The victim's clothing should be collected, sealed and labeled. Fresh clothes should be provided.
5. Any loose hairs or debris in the pelvic area (pubic hairs of the assailant are looked for) should be collected. In some cases, some of the victim's pubic hairs are needed and 15-20 of the victim's head hairs (to differentiate the victim's hairs from the assailant's).
6. Fingernail scrapings are collected for detection of blood or tissue.
7. Examination of the victim for evidence of semen and, if detected, it is collected.
8. Swabs are taken from the vaginal, anal, and oral areas to check for semen, sexually transmitted diseases, and infections.
9. In cases the examiner feels a DNA sample is required for PCR, the same is taken if the patient gives consent.
10. Prophylactic treatment is administered against tetanus, sexually transmitted diseases, and other common infections.
11. The pelvic examination is always performed by a gynecologist.

The evidence collected is sealed, labelled and handed over to the Investigation officer for further lab tests to be conducted in respective forensic laboratories.
The rape accused if identified, should also be subjected to investigation as soon as possible.
Corroborative evidence (e.g. bed sheets or couch cushions that may contain trace evidence linking the assailant to the scene, grass leaves for palynological evidence etc.) should be collected from the alleged crime scene.
Points to remember:
· A rape victim should immediately be referred to a victim support setup.
· The victim should be given the choice to make a statement.
· An investigating officer should be available to take her for a medical examination within the hour of reporting.

· The investigating officer should find out the perpetrator’s details from the victim and arrest him immediately, if possible.
· The victim should always be provided with transportation to her home.
· The investigating officer should arrange to regularly follow up with the victim about the investigation.
· The victim should be informed about any arrests or court appearances.

Petechiae in asphyxial deaths

2008-12-15T22:30:00.003+05:30

Asphyxia is the interference with the intake or utilization of oxygen, combined with the failure to eliminate carbon dioxide.

Petechiae are pinpoint-sized red dots under the surface of the skin. The dots are red because they contain blood that has leaked from tiny blood vessels (capillaries) into the skin.

Conjunctival and facial petechiae, although nonspecific findings, are considered hallmarks of asphyxial deaths. Despite the common knowledge that they are neither predictable findings in all asphyxial deaths nor rare in natural, non-aphyxial deaths, the belief persists that petechiaeare corroborative evidence of asphyxia.

Excluding those related to infectious, coagulopathic, or micro-embolic aetiologies, petechiae of the head are the product of purely mechanical vascular phenomena: namely, impaired or obstructed venous return in the presence of continued arterial input. As pressure builds in venules and capillaries, particularly those with little surrounding connective tissue support, such as the conjunctivae and eyelids, vascular rupture produces petechiae. The likelihood of this occurrence is directly proportional to the degree of venous obstruction and inversely proportional to that of arterial compression at or above the level of the heart. Nearly 2 kg of pressure is required to compress the jugular veins, whereas 5 and 30 kg are required to compress the carotid and vertebral arteries, respectively. Therefore, an intermediate amount of force simultaneously applied to both results in venous compression before arterial .This is similarly applicable to the right and left sides of the heart. If the compressive pressure to the chest or neck is great enough to obstruct venous return from the head, but not enough to obstruct arterial flow to it, cephalic venous pressure will rise, as will the probability of small vessel rupture. A violent struggle that increases cardiac output and raises blood pressure therefore enhances the occurrence of petechiae. On the other hand, if the applied force is sufficiently great to obstruct arterial flow, venous engorgement and rupture will not occur.

Patterns in the relationship between mental disorders and crime

2008-12-13T22:02:00.004+05:30

· Pattern 1 offenders are those for whom crime is a response to psychotic symptoms, most often delusions or hallucinations.
· Pattern 2 offenders commit crimes motivated by compulsive desires, such as sex offenses by paraphiles and offenses regarded as evidence of disorders of impulse control.
· Pattern 3 offenders are those with personality disorder for whom the crime is merely one example of a maladaptive pattern of voluntary and knowing behaviour.
· Pattern 4 offenders have coincidental mental illness that is unrelated to the crime.
· Pattern 5 offenders are those who become mentally disordered or feign mental disorder as a result of their crimes, such as those who dissociate upon seeing what they have done, those who become depressed in prison, those who become psychotic on death row, and those who malinger mental illness.

(Int J Law Psychiatry)

Although these categories do not determine whether offenders are responsible for their behaviour, some unknown proportion of Pattern 1 offenders do meet legal criteria for insanity, depending on the facts of each case and the applicable legal standards. It is arguable whether or not Pattern 2 offenders ever meet legal criteria of insanity. Offenders evidencing only Patterns 3, 4, or 5 are not candidates for an insanity defence.

There is therefore a need for researchers and policy makers in the area of mental health and law to collaborate and develop common methods of approach to research. Despite the knowledge of prevalence of mentally ill offenders in jails and prisons, there are a number of research questions that remain. The relationship between substance abuse and mental disorders has also been a topic not very well researched. It is significant because a lot of substance abuse offenders, also happen to be mentally ill offenders.

Future Approach

2008-12-11T20:45:00.007+05:30

The difference now as compared to before is the anger among people in India. Not against just the political parties, not against any particular individual, but the system in general that has been corroded over the years by reasons that can be hard to explain. Perhaps, the only good to have come out of the terrorist attack was that it has woken the people to come together and demand for a concrete action.

Like in the Western countries, we need to develop a proper terror protocol. It should spell out the actions to be taken in an event of a terror strike.

The government has made the right noises by deciding to set up a federal agency for the same. What this would do is coordinate the different teams of people involved in tackling the situation. What we need are not only well trained cops/commandos, we also need experts in the field of intelligence. Experts who are good at research, who can assess situations. Do not undermine the role of a psychoanalyst here as well. We need people who are good in Information and Technology. Military should always have a say in security issues.

Prosecution and conviction has to be immediate. Perhaps we need another K.P.S. Gill like individual in charge here. We all know how he singlehandedly wiped out both terrorism in Punjab and Hockey in India! He was one man who perhaps idealised Hammurabi: eye for eye, tooth for tooth. Perhaps harsh for our times, but they only seem to understand their own way of thinking.

Some have suggested that the Indian Muslims should step in. I agree. For a country that holds the second largest Muslim population in the world (after Indonesia), calling Muslims in India a minority community is almost laughable. Indians admire their Muslim icons. From superstars to film stars. When they speak, people listen.

Other thing that can be done is go to the grassroots. Beat them at their own game. Teach the kids at madras and other places where they are educated, the true meaning of Islam. Teach them what 'Jihad' means (I will talk about it in my next blog). Keep in mind, what they can do, we can do better!

Remember, prevention is important, but equally important is the cure. And the way to fight terrorists is to terrorise them. Make the bastards bleed so that the others in waiting think twice before stepping into their shoes.

Digital Forensics

2008-12-09T12:18:00.002+05:30

There are “myths” surrounding evidence admissibility that are common to digital forensics. I’ll focus on the two most common (that I’ve seen):
Digital evidence is easy to modify and can’t be used in court
Only certain types of tools generate admissible evidence
The first myth focuses around the idea that digital evidence is often easy to modify (either accidentally or intentionally.) This really focuses on the reliability requirement of evidence admissibility. The short answer is that digital evidence is admissible. In fact, unless there is specific support to a claim of alteration (e.g. discrepancies in a log file) the opposing side can not even raise this possibility (at least for admissibility purposes.) Even if there are discrepancies, the evidence is likely to still be admitted, with the discrepancies going towards the weight of the evidence rather than admissibility. The exception to this might be if the discrepancies/alterations were so egregious as to undermine a “minimum standard of trustworthiness.” (Picture courtesy: www.fieldsassociates.co.uk)
The second myth is commonly found in the form of the question “What tools are accepted by the courts?” I think a fair number of people really mean “What tools generate results that are admissible in court?” Realize that in this case, “results” would be considered evidence. This scenario is somewhat analogous to a criminalist photographing a physical crime scene and asking the question “What cameras are accepted by the courts?” As long as the camera records an accurate representation of the subject of the photograph, the results should be admissible. This would be some “minimum standard of trustworthiness”. To contrast this to weight, realize that different cameras record photographs differently. A 3 megapixel camera will have different results than a 1 megapixel camera. An attorney could argue about issues surrounding resolution, different algorithms, etc. but this would all go to the weight (persuasive factor) of the evidence, not the admissibility.
There is always a lot of conversation about when digital evidence is and is not admissible.
In the legal system, before evidence can be presented for persuasive use, it must be admitted by the court. If one side or the other raises an objection to the evidence being admitted, a judge will typically listen to arguments from both sides, and come to a decision about whether or not to admit the evidence. The judge will likely consider things like admissibility requirements (listed below), prejudicial effects, etc.
When it comes to court, the rules for what is and what is not admissible vary. There are however three common elements:
Authenticity
Relevancy
Reliability
There are two primary categories of digital forensics tools, those that acquire evidence (data), and those that analyze the evidence.
Acquiring is actually the easier of the two tools. There are a number of acquisition tools in existence. There are two ways of storing the acquired data, on a physical disk (disk to disk imaging) and in a file (disk to file imaging).
Analysis tools work in two major phases. In the first phase, the tools read in the evidence (data) collected by the acquisition tools as a series of bytes, and translate the bytes into a usable structure. The second phase is where the analysis tool examines the structure(s) that were extracted in the first phase and performs some actual analysis. This could be displaying the data to the screen in a more-human-friendly-format, walking directory structures, extracting unallocated files, etc.
Presentation of digital evidence (and conclusions) is an important part of digital forensics, and is ultimately the role of the examiner, not a tool. Tools however can support presentation. EnCase allows an examiner to bookmark items, and ProDiscover allows an examiner to tag “Evidence of Interest”. The items can then be exported as files, to word documents, etc. Some analysis tools have built in functionality to help with creating a report.
Of course, there is a lot more to the implementation of the tools than the simplification presented here, but this is the basics of how digital forensics tools work.

Forensic Accounting

2008-12-08T15:48:00.003+05:30

It’s no secret that society is wholly upset with the failing economy, and unemployment woes are making headlines every day. The pressure of the approaching holidays and nationwide job security fears are combining to form a perfect storm in which corporations are at risk for increased incidents of accounting fraud.
As more layoffs are announced each day across the United States and salary increases remain stagnant, disgruntled employees are turning to alternative methods of increasing their cash flow, and your company may be suffering as a result.
Now is the time to be aware of discrepancies in your financial records. CEO’s of major corporations aren’t the only ones looking for a bailout, and your employees may be helping themselves to extra funding at your company’s expense.
The motives causing employees to resort to accounting fraud during the holidays are varied; they may be attempting to offset losses in the market, or in their 401K and retirement funds; they may be concerned about job security and are seeking to get whatever they can before possibly facing unemployment; they may simply be desperate for extra spending cash during the holiday season.
If you suspect financial fraud within your organization, then you’ll need a certified forensic accountant to conduct a thorough investigation. The certified forensic accounting team at Kessler International specializes in fraud detection, and their extensive training and professional experience with forensic accounting will ensure that you have one less thing to worry about this Christmas season.
(Courtesy Kessler International)

Soft Target

2008-12-04T22:20:00.003+05:30

So what is a ‘soft target’ for terrorists? (Cartoon courtesy: joshuapundit.blogspot.com) Not something that can be taught during counter-terror groundwork. It can vary from place to place, and more importantly, from one terrorist to another. Care should be taken not to assume that only high profile places or crowded markets would be vulnerable. Let’s face it. Any and every site is susceptible for militants to strike. For it may not necessarily be just attention that they are seeking or inflicting fear in the community. Do not disregard the fact that these individuals are criminals. They always have an ulterior motive in each and every one of their acts.
Let us take the example of Delhi, my hometown. Just today the Tees Hazari courts had to be vacated because of a bomb hoax. I do not know how many of you would have been to Delhi. But those of you who know a bit about India’s capital, would know what the vulnerable targets in Delhi are. Let us see. Tees Hazari is already mentioned above. What else? Parliament House, all the big malls, crowded market places, underground parking(s), metro-stations, schools, colleges.......... The list could go on.
Now, how many of you have thought about the other ‘less’ significant targets? Let me give you some examples. I do not intend to create panic here, all I want to do is to try and make people aware that anything is possible.
Stick around the underground Metro Stations at night; nobody is going to check if or not all have left. Blow up the tunnel. What happens? Maybe nobody gets hurt. It sure does create panic. Similarly, one could blow up the bridges on Yamuna or more than one of the many petrol stations on the highways. What about the many dhabas on the Jaipur Highway?
There are so many banks in Delhi being guarded by that one emaciated guard with an empty double barrelled shot-gun and the expired faded red cartridges. Most of the government banks I have been to, do not even have security cameras or alarms. Could money be a factor here? I wonder
Personally though, my biggest fear is none of the above. Think of a target which if attacked upon, the terrorists could get help from within. All they would have to face for resistance are cops with their ancient .303s, 9mms, and the Indian imitation of AK47s (sorry, but I would trust them as much as I trust the Uzis our Black Cats use. They jam when you need them the most). Tihar Jail happens to be the biggest prison in India, where all the high profile criminals share quarters with the most dreaded terrorists we have ever caught. Now that is how I would define a nightmare.
We can assume what the next target would be and hope to be prepared for it. I just hope they are more stupid than I think they are. If anybody who reads this can, please bring this to the attention of the concerned authorities. There are a couple of more sites I could mention here, but I fear that if you are reading this, so could they.

What makes them do what they do??

2008-12-01T19:36:00.002+05:30

I came across this interesting stat this morning according to which, although the total volume of terrorist incidents world-wide has declined in the 1990s, the proportion of persons killed in terrorist incidents has steadily risen.
Though religion and terrorism share a long history, in recent decades it has largely been associated with ethnic- and nationalist-separatist or ideologically-motivated agendas.
There is no “terrorist personality”, nor is there any accurate profile – psychologically or otherwise – of the terrorist. How would one profile these terrorists then? Research on the psychology of terrorism is very limited. Cultural factors are important, but have rarely been studied.
An individual could become terrorists in different ways, in different roles, and for different reasons. It may be helpful to distinguish between reasons for joining, remaining in, and leaving terrorist organizations. Injustice, need for identity and need for belonging are common vulnerabilities among potential terrorists. Histories of childhood abuse and trauma and themes of perceived injustice and humiliation often are prominent in terrorist biographies, but do not really help to explain terrorism. “Narcissistic rage” is perhaps the primary psychological precipitant of terrorist aggression. In radical extremist groups, many prospective terrorists find not only a sense of meaning, but also a sense of belonging, connectedness and affiliation.
Terrorist ideologies tend to provide a set of beliefs that justify and mandate certain behaviours. Those beliefs are regarded as absolute, and the behaviours are seen as serving a meaningful cause (McCauley, C. R., & Segal, M. E. Social psychology of terrorists groups).
Mental illness is not a critical factor in explaining terrorist behavior. Most terrorists are not “psychopaths.”

Mumbai tragedy: How should the forensic experts approach?

2008-11-29T18:19:00.003+05:30

The Mumbai ordeal is finally over. Hope all gets back to normal. I wish they would have killed Raj Thackeray as well. But then he would have been portrayed as a martyr. Glad the bastard is safe.
I shall be updating on the way a scene like this should be approached by forensic experts soon.

Forensic Anthropologist

2008-11-21T20:15:00.000+05:30

Forensic Anthropologists are often called upon to contribute by opining on the cause of death of skeletonised human remains. The same requires a sound knowledge of trauma assessment. "The forensic anthropologist specializes in hard tissue morphology, structure and variability. In those cases in which soft tissue has been degraded by time, temperature, environment or other external forces, the only tissue remaining more or less intact is bone. The obvious person to call in to evaluate such material is the bone specialist. Moreover, it should be not just your garden-variety osteologist, but one who's trained in the medico-legal context where it is essential to be able to unerringly distinguish among ante-, peri- and post-mortem defects, and where time since death is a significant factor" .
Though the success of creating a biological profile is largely dependent on the preservation and/or condition of remains at the point of their accession, analysis of the characteristics is undertaken by direct comparison of remains with standard physical, or graphic, exemplars or by the application of mathematical models developed from reference populations. The construction of the biological profile is thus undertaken in a set sequence which includes assessment of ancestry, sex, age, stature, and individuating characters. Once the biological profile for an individual is constructed, the Forensic Anthropologist submits their illustrated final report to enable them to draw together all the lines of evidence that may help to support identification.
The success of creating a biological profile is largely dependent on the preservation and/or condition of remains. Some environmental conditions like acidic soil, humidity etc. are particularly detrimental to the preservation of bones. Other factors like explosion and/or fire can result in the forceful breakup of the human body. The approach and success of each case is therefore wide-ranging.
More often than not, it is the pathologist or medical examiner who calls the forensic anthropologist in for consultation. The pathologist may tell the anthropologist what he expects, thereby setting the ‘tone’ of the work. Forensic anthropologists generally work with forensic pathologists, odontologists, and homicide investigators to point out evidence of foul play and assist with time of death estimates.
Injury and damage to the skeleton or soft tissue of the body may come easy, however only some certain type of injuries actually affect the skeletal remains themselves. Where Peri-mortem injury can provide information on Cause of Death/Manner of Death, Ante-mortem injury (healed) and disease markers on bone can provide information important to an individual’s identification. Post-mortem injury may provide information unrelated to death, but can be significant in context of remains (taphonomic factors) or treatment of corpse after death.
How a bone responds to traumatic insults can depend on the mechanical properties of bones, the type of fracture, the extent of repair, and the type of trauma.
One must keep in mind that a bone is ‘visco-elastic’ in nature and will therefore deform when subjected to force. Fracture results when the force subjected is greater than the bearing capacity of a bone. The general rules of fracture are:
· New fracture lines do not cross old ones
· Fracture lines usually follow directions of weakness in the bone (points of least resistance)
· If a fracture runs into a bony buttress in the cranium (I.e. brow ridge, nuchal lines), the fracture can make up to a 90 degree turn to run parallel to the buttress.
Fracture repair follows the following phases (Bailey and Love, Essentials of Surgery, 2006):
1. Stage of Inflammation (formation of hematoma, influx of fibroblasts, osteoprogenitor and chondroblast cells.) Stage lasts up to 4 days.
2. Stage of soft callous formation. This stage lasts for 3-4 weeks.
3. Stage of Hard Callous formation. It is in this stage that bone union is attained. This stage begins at the end of stage of soft callous formation and lasts for 2-3 months.
4. Stage of Remodelling. This is the stage of callous reduction and when the bone restructures into its original shape. This stage can continue for several years.

The type of Trauma can be classified into (Christopher Bulstrode, Oxford Textbook of Orthopedics and Trauma, 2007):
1. Blunt Force Trauma: When the injury is caused by a force with a wide area of impact. This is commonly seen in road traffic accidents, falls or when an individual is attacked with some kind of a bludgeoning instrument like a club etc. The fracture seen in these cases may be of two types. (a) If the force is applied slowly, like in case of being run over by a car, the fracture is simple in nature. (b) If the force applied is excessive, then it can result in comminuted fracture where a bone shatters into small fragments.
2. Sharp Force Trauma: When the injury is caused by a force with a narrow area of impact on the bone e.g. a pointed or a sharp edged weapon. This results with the Dynamic Force concentrating over a narrow area. In this case, Puncture/chop marks are seen if force occurs perpendicularly and into the bone. If get force occurs along the surface, Incision marks result (e.g. in slashing actions; stabbings that graze surface).
3. Projectile Trauma: This includes gunshot trauma. This follows a distinct characteristic response. Dynamic forces apply with narrow focus that widen as they pass through bone. Factors influencing this type of trauma are the range of fire (Contact wound, Point Blank wound, Intermediate and long range wounds) the direction of projectile in relation to the bone, the calibre of the weapon.
Sometimes the Forensic Anthropologists are called upon to analyze remains that have been exposed to fire. Intense heat modification to bone results in fragmentation, colour changes, shrinkage etc. which can make a forensic osteological analysis (including the determination of basic biological parameters) complicated. The analysis of bone trauma in these cases can be especially difficult. One must remember that Sharp Force Trauma (SFT) evidence is typically exhibited in the form of subtle marks left on the bone that even experienced analysts may have difficulty identifying; it is assumed that exposure to fire results in complete loss of those details. As such, evidence of SFT may be even more likely to remain undiscovered.
It is essential for Forensic scientists to understand concept of the peri-mortem interval because it may provide important information about the cause and manner of death. A peri-mortem injury is usually defined as an injury at, near, or around the time of death. The peri-mortem interval, however, is often viewed as an ambiguous and elastic interval of unspecified duration. A common characteristic of peri-mortem bone fractures is usually sharp edged whereas right-angled edges are characteristic of dry bone fractures (Villa P, Mahieu E. Breakage patterns of human longbones. J Hum Evol 1991). The presence of fracture lines and the jagged surface of the broken ends are also said to distinguish peri-mortem from post-mortem injuries. A peri-mortem determination is therefore made with caution and includes several important features.
One can therefore safely conclude that it is of the utmost importance that the recovery of human remains from different scenarios be carried out by individuals with extensive training in osteology, taphonomy, and archaeological methods. And it is because of these factors that the role of a Forensic Anthropologist so significant in any forensic investigation.

Duties of a Forensic Anthropologist

2008-11-05T20:09:00.000+05:30

The application of anthropology to human body/remains for legal purposes is called Forensic Anthropology. Though it is not a new field on its own, the role of a Forensic Anthropologist is still a vital one and one that is often called upon for the ‘missing clues’ in the big jig-saw puzzle of Forensic Science. Among the first instances where the importance of role of a Forensic anthropologist was highlighted, involved in the exhumation and identification of victims of war, ethnic cleansing and genocide who began the exhumation of mass graves in the early to mid eighties.

A forensic anthropologist is a physical anthropologist that has been trained to recognize and examine human skeletal remains for indications of sex, age, height, unique characters of the individual, features which might indicate how the person died, and processes that affect the skeleton after death. Although a forensic pathologist or other medical doctor may seem a more appropriate conductor of such analyses, their education and training focuses on changes in soft tissue. The forensic anthropologist is expected to recognize bone outside of its natural context even if it is reduced to small fragments. He or she can identify all the bones of the human skeleton, determine if a bone is human or not, and understand that the shape of a bone is related to its function in the body and its owner's relationship to other animals (Phoebe Stubblefield and Lesley M. Rankin-Hill. History Uncovered: Skeletal Remains as a Vehicle to the Past).

In quite a few instances, the only remains of a deceased found are the bones. It is in these instances that a Forensic Anthropologist’s assistance is called upon. The forensic anthropologist is commonly requested to perform the following duties:
1. To determine if the bones are those of human or animal.
2. To determine if the bones are of a single individual or of more than one person
3. Determination of the age, sex and race of the bone (Biological Profile).
4. Sometimes the bones can reveal if the individual whose bones are presented was suffering from certain chronic diseases like osteoporosis or tumours. Traumatic history of an individual (both recent and healed) can also be determined by an observant eye.
5. Provide testimony in a Court of Law.
Dr. Momanchand (Forensic Anthropologist, RIMS) states aptly that identification of victims becomes a challenging task for an investigating team and forensic anthropology can make a major breakthrough.
Forensic Anthropologists draw their conclusions based on multidisciplinary methods derived not only for osteology and skeletal biology, but also archaeology which is a pivotal tool of Forensic Anthropology. It is through the archaeological techniques that Forensic Anthropologists are able to assist in detection and recovery of human remains (role of forensic anthropologist in identification of unknown, Biren Singh, 06). With the advent of computer technology, more and more countries are now adapting the auxiliary techniques such as creation of visages from the skull and photo-superimposition as techniques which often fall within the expertise of a forensic anthropologist (Haglund and Rodriguez 1998).

Forensic Anthropologists are not usually assigned to work alone. Often their task integrates all four fields of anthropology (biological, cultural and linguistic, and archaeological) as well as a variety of other disciplines including pathology, odontology, criminalistics and law. These cumulate a great influence on the process of investigation and, ultimately on the identification of victim(s).

It is the duty of a Forensic Anthropologist to maintain the scientific integrity of the investigation, conform to appropriate legal conventions of the investigation and to fulfil his/her responsibility to the community affected by the events (Maples, \V. R. 1998. 'Trauma Analysis by the Forensic Anthropologist' in Reichs, K.(ed)). In recent years the scope of a Forensic Anthropologist has expanded in medico-legal investigation. It has also developed within the increasing number of international human rights forensic projects with which the anthropological community has become inextricably involved (Komar, D. 1003. 'Lessons from Srebrenica: the contributions and limitations of physical anthropology in identifying victims of war crimes', Jozirnnl of Forensic Sciences 48:4). While the techniques involved in the above cases are similar, it is imperative that the forensic anthropologist is flexible in his approach. A forensic anthropologist is expected to know how to cope with situations where the ideal protocol and methodology are both followed. At the same time, in situations where they are either not pragmatic or unavailable in a given situation, he/she must know what of the 'ideal' may be eliminated without losing necessary information (Ruma Parkait, Recent trends in forensic anthropology, 2003).

The varieties of occasion that require the skills of a forensic anthropologist are sufficiently diverse that the anthropologist may enter the project at various points and utilize a wide assortment of skills (Modi, 1999). The common activities include:
1. Scene research (local and locality) for skeletal remains or burials.
2. Recovery of remains by surface recovery or excavation.
3. Laboratory examination and inference.
4. Report assembly.

Like in any typical crime scene analysis, the anthropologist maps the locality in order to have a record of the position of the remains relative to a fixed landmark and any significant features of the site. The site is located on a map and the physical address of the location is recorded. In wooded areas or along roadsides the forensic anthropologist employs a Global Positioning System (GPS) unit to get the geographic coordinates of the site. When a burial is involved, the site is mapped with the location of the burial indicated (sometimes the burial is the site), while the burial itself receives a mapping grid. This is followed by organized and thorough excavation which may provide the information that allows the reconstruction of the events surrounding the burial of the deceased. This is a technique not unique to anthropologists alone, and is also employed by taphonomists and palynologists among others. The forensic anthropologist must ensure good note taking, photography and/or videotaping during the excavation for a good record of what was found during the excavation. Once human remains are found, the anthropologist ensures the material remains in association, and prevent fragile material from further breakage or deterioration from extrinsic factors such as exposure to air and sunlight. The remains are then maintained in a secure location while the anthropologist conducts the analysis. Good security ensures the remains and any items with them stay together and are not adulterated or altered by outside influences.
One can thus conclude from the above paper that a forensic anthropologist is a vital cog in the very complex and diverse forensic machinery.

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FORENSIC APPLICATION OF CHEMISTRY IN TOXICOLOGY

2008-09-14T09:43:00.001+05:30

Over the past century, forensic chemistry has become an essential part of almost every criminal investigation. A forensic chemist is a scientist who analyses physical evidence as found on a victim or at the scene of a crime. These scientists work in the field of criminalistics, which deals with analysis, comparison, identification, and interpretation of physical evidence to prove the connections to or existence of a crime. Evidence is examined right down to the molecular level and the compositions of samples are calculated. Criminalists provide information to investigators, attorneys, judges, or juries to help determine the innocence or guilt of a suspect. Forensic chemists may perform one or more of the following tasks:
• Identify illicit drugs.
• Analyse drugs and poisons in human tissue and body fluids; including blood alcohol determinations.
• Examine and compare materials such as fibres, paints, cosmetics, oils, petrol, plastics, metals, soils and gunshot residues.
• Examine items of human and animal biological material to be compared with victims and suspects using DNA profiling.
• Conduct botanical identification of plant materials at trace levels, and whole-plant identifications.
There are many areas in forensic chemistry, but this report focuses on three main areas, which are of the greatest relevance to chemistry. They are: Trace Analysis, Toxicology and Serology. The analytical techniques involved in forensic analysis are shown in the flowchart attached to Appendix 1 of this report TRACE ANALYSIS. The trace analysis applications in forensic chemistry include the analysis of many substances such as gunshot and primer residue, paint, hair, and fibres. This substance range from being microscopic to macroscopic in size. Paint Analysis Paint analysis is especially useful in hit-and-run cases, where paint is usually left at the scene of a crime. The paint is first analysed by Gas Chromatography and then by a Scanning Electron Microscope. The first method is used for comparing the organic binder in the paint with that of a standard (for example, paint from a suspect's vehicle), and the scanning electron microscope is used for identifying the constituents of the inorganic pigments present in the paint. Hair and Fibre Analysis Hair and fibre analysis is usually performed by comparison microscope work, where a known standard is physically compared to the evidence. A polarizing microscope is especially useful for fibre analysis to help identify the class of fibre under inspection. Arson Analysis Forensic arson analysis deals with the analysis of fire debris for the presence of accelerants. Some common accelerants found in arson cases are petrol, diesel, and lighter fluid. Fire debris submitted for arson analysis is packaged in sealed containers, such as mason jars, that are sterile to prevent contamination of the sample. The chemist performs the analysis by inserting activated charcoal (C-strips) into the "headspace" of the sealed container. The C-strip is subsequently removed from the container and placed in carbon disulfide. The accelerants desorb from the C-strip and dissolve into the solvent. This solution is then injected into a Gas Chromatograph. Gas Chromatography Gas Chromatography is the most sensitive of all the chromatographic techniques. It is capable of measuring as little as 10-12grams of a compound. Once a sample is ready to be analysed, it is placed into the injection port of the gas chromatograph. The injection port is heated to a temperature that is sufficient to instantly vaporise the sample. The vaporised sample is then swept into a column by a carrier gas. The carrier gas is usually nitrogen; it is often used because it is an inert gas and will not react with the sample and cause error. The column consists of a series of glass coils, which are only about 4mm in diameter. These coils are packed with a porous solid that has been coated with a high-boiling liquid hydrocarbon. The liquid acts as a liquid stationary phase. The components of the sample repeatedly pass into and out of solution with the stationary phase. The least soluble components are swept out of the column first by the carrier gas, into the detector. The detector calculates the time it takes for separate components to pass through the column. By knowing the time it takes, and the amounts of the substances present, a graph can be drawn and the constituents of a sample calculated.

Forensic toxicology deals with qualitative and quantitative analysis of biological specimens for the presence of alcohol, drugs, and/or poisons and their corresponding metabolites. Investigations often involve driving-under-the-influence of alcohol.

Drug Analysis
The major area in toxicology is drug analysis, which deals with the identification of illicit drugs. Because of the increased popularity of cocaine, the majority of drug analysis cases involve cocaine analysis, along with other spot tests for the detection of opiates (such as heroin and morphine), amphetamines, barbiturates, marijuana and lysergic acid diethylamide (LSD). Gas Chromatography and Mass Spectroscopy are the most often used laboratory techniques for drug identification. Mass Spectroscopy Combined with a gas chromatograph, a mass spectrometer is probably the most powerful tool available to a forensic chemist dealing with drug analysis. Mass spectrometry is a powerful analytical technique that is used to identify unknown compounds, to quantify known compounds, and to elucidate the structure and chemical properties of molecules. Detection of compounds can be accomplished with very minute quantities (as little as 10-12mg). This means that compounds can be identified at very low concentrations in chemically complex mixtures. When samples such as blood are to be analysed for drug content, the sample is first vaporized and then injected into the main body of a mass spectrometer. The gaseous sample is then admitted through a small inlet into an ionisation chamber. Here the sample is bombarded with electrons, forming ions with a single positive charge. The positive ions are accelerated to high speeds by an electric field until they enter a region where there is a perpendicular magnetic field. This field causes the ions to move in curved paths, with a radius dependant on the mass to charge ratio of the ions. Only ions with a particular radius will reach the collector. By changing the accelerating voltage or the strength of the magnetic field, ions of different masses can reach the collector. The collector measures the current due to the different ions and the data is recorded as a mass spectrum. It is in these mass spectrums that chemicals such as drugs can be identified. The mass spectrum of cocaine demonstrates how a forensic laboratory might determine the nature of an unknown street drug.

Forensic serology deals with the study of body fluids that might have probative value in the prosecution of a crime. Typical fluids are blood, semen, and saliva. After testing to identify these substances, it is possible to begin to identify the donor of the material by testing for "blood group substances" (from the ABO blood group system) or other proteins that are polymorphic. DNA Analysis Forensic DNA analysis deals with the identification of the source of a body fluid through DNA testing. Fluids, which are often left at the scene of a crime, which contain DNA, are blood, semen and saliva. The chemical structure of everyone's DNA is the same. The only difference between individuals is the order of the base pairs, which make up the structure of DNA. A newly developed technique called “DNA fingerprinting” utilises these different base pair sequences to identify an individual. DNA Fingerprinting DNA fingerprinting has established itself as an efficient and highly accurate means of determining identities and relationships. It has practically revolutionized the field of forensics, especially concerning rape cases. DNA fingerprinting is achieved by using the laboratory technique known as gel electrophoresis.

Gel electrophoresis is the best method for the separation and qualitative analysis of very large molecules that have an overall charge. It is similar in many ways to chromatography. The process of electrophoresis for DNA fingerprinting is summarised below.
1. DNA is extracted from blood, semen, hair roots or other body tissues.
2. Strands of DNA are cut into fragments using a restriction enzyme.
3. The DNA fragments are separated into bands during electrophoresis.
4. The DNA band pattern is transferred to a nylon membrane.
5. A radioactive “probe” binds to bands on the membrane.
6. X-ray film is placed next to the membrane to detect the radioactive pattern.
The film is developed to create a permanent “fingerprint suitable for examination.”

With the laboratory techniques listed so far in this report, plus many others, forensic chemists are able to determine what happened at the scene of a crime. They have the power and authority to identify a criminal, and just as importantly, clear an innocent suspect. Forensic chemistry is always improving as new advances in technology take place. Research in this field is focused upon finding new ways of analysing collected evidence that are cost effective and give fast and precise results.
This report outlines the significance chemistry has in criminal investigations. Three major areas of forensic chemistry are outlined including: Trace Analysis, Toxicology and Serology. Methods of analysis such as Gas Chromatography, Mass Spectroscopy and Electrophoresis are also summarised.

Chromatography

Chromatography is a method of separating substances that make up a liquid or gaseous mixture. One use of it is to measure or identify low concentrations of substances, such as pollutants in air or water. Another use is to separate and identify products of chemical reactions. Chemists use this method to separate pure substances from impurities. Chromatographic methods are based mainly on a process called adsorption. A mixture passes through a solid or liquid material that adsorbs to substances. This material is called an adsorbent. A liquid or gas added to the mixture helps move it through an adsorbent. Various substances are adsorbed at different rates of speed, so the substances in a mixture separate from one another as the mixture moves through the material. Common chromatographic methods are liquid column, thin layer, and gas chromatography. Liquid Chromatography For compounds that cannot be volatilized readily, the liquid chromatograph can be used instead of the gas chromatograph. The stationary phase consists of a finely powdered solid adsorbent packed into a thin metal column and the mobile phase is made of an eluting solvent forced through the column by a high-pressure pump. The mixture that needs be analyzed is injected into the column and monitored by a detector. Many different liquid chromatograph packing and eluting solvents are available to achieve the desired resolution. Thin-Layer and Paper Chromatography. A layer of adsorbent also can be spread on a glass plate, instead of packed into a column, for analytical purposes. By means of a thin capillary tube, the plate is spotted with a solution of the mixture that is to be resolved, and the solvent is allowed to evaporate. An eluting solvent is then allowed to move up the plate by capillary action, drawing the components of the mixture along by varying degrees. Spraying it with an oxidizing agent develops the plate, so that each component becomes charred and appears as a dark spot on the plate. The location and size of the spots serve to identify and measure the relative quantities of the components. As in column chromatography, polar substances will not elute as well and will remain nearer the bottom of the plate, while non-polar substances will elute to the top. This process is called thin-layer chromatography. In paper chromatography a procedure similar to thin-layer chromatography is used except that the cellulose in the paper acts as the adsorbent. The gas chromatograph is a system consisting of a liquid with a high boiling point impregnated on an inert solid support as the stationary phase and helium gas as the mobile phase. The stationary phase is packed into a thin metal column and helium gas is allowed to flow through it. The column is attached to an injection port, and the entire system is heated in an oven. A solution of the mixture is injected into the column through the injection port by means of a syringe and is immediately volatilized. The helium gas then sweeps the components out of the column and past a detector. The polarity of the compounds and their volatility determines how long the column retains them. When each component passes the detector, a peak is registered on a recorder. The relative quantities of the components can be determined from the relative areas under the peaks. By varying the polarity of the column and its temperature, many different resolutions can be carried out. Since the capacity of gas chromatograph columns is very low, the gas chromatograph is used chiefly as an analytical tool, although it can be used for preparative purposes as well. Miniaturized gas chromatograph instruments have been employed in space probes to analyse the atmospheres of other plane.

So how does a mass spectrometer work? Mass spectrometers can be divided into three fundamental parts, namely the ionisation source, the analyser, and the detector. The sample under investigation has to be introduced into the ionisation source of the instrument. Once inside the ionisation source the sample molecules are ionised, because ions are easier to manipulate than neutral molecules. These ions are extracted into the analyser region of the mass spectrometer where they are separated according to their mass (m) -to-charge (z) ratios (m/z). The separated ions are detected and this signal sent to a data system where the m/z ratios are stored together with their relative abundance for presentation in the format of a m/z spectrum. The analyser and detector of the mass spectrometer, and often the ionisation source too, are maintained under high vacuum to give the ions a reasonable chance of travelling from one end of the instrument to the other without any hindrance from air molecules. The entire operation of the mass spectrometer, and often the sample introduction process also, is under complete data system control on modern mass spectrometers. The method of sample introduction to the ionisation source often depends on the ionisation method being used, as well as the type and complexity of the sample. The sample can be inserted directly into the ionisation source, or can undergo some type of chromatography en route to the ionisation source. This latter method of sample introduction usually involves the mass spectrometer being coupled directly to a high pressure liquid chromatography (HPLC), gas chromatography (GC) or capillary electrophoresis (CE) separation column, and hence the sample is separated into a series of components which then enter the mass spectrometer sequentially for individual analysis. Many ionisation methods are available and each has its own advantages and disadvantages. The ionisation method to be used should depend on the type of sample under investigation and the mass spectrometer available. Ionisation methods include the following: Atmospheric Pressure Chemical Ionisation (APCI) Chemical Ionisation (CI) Electron Impact (EI) Electrospray Ionisation (ESI) Fast Atom Bombardment (FAB) Field Desorption / Field Ionisation (FD/FI) Matrix Assisted Laser Desorption Ionisation (MALDI) Thermospray Ionisation (TSP). The ionisation methods used for the majority of biochemical analyses are Electrospray Ionisation (ESI) and Matrix Assisted Laser Desorption Ionisation (MALDI). With most ionisation methods there is the possibility of creating both positively and negatively charged sample ions, depending on the proton affinity of the sample. Before embarking on an analysis the user must decide whether to detect the positively or negatively charged ions separation of Sample Ions. The main function of the mass analyser is to separate or resolve the ions formed in the ionisation source of the mass spectrometer according to their mass-to-charge (m/z) ratios. Various mass analysers have different features, including the m/z range that can be covered, the mass accuracy, and the achievable resolution. The compatibility of different analysers with different ionisation methods varies. For example, all of the analysers can be used in conjunction with electro-spray ionisation, whereas MALDI is not usually coupled to a quadruple analyser.

Tandem (MS-MS) mass spectrometers are instruments that have more than one analyser and so can be used for structural and sequencing studies. Analysers do not necessarily have to be of the same type, in which case the instrument is a hybrid one.
The detector monitors the ion current, amplifies it and the signal is then transmitted to the data system where it is recorded in the form of mass spectra. The m/z values of the ions are plotted against their intensities to show the number of components in the sample, the molecular weight of each component, and the relative abundance of the various components in the sample. The type of detector is supplied to suit the type of analyser; the more common ones are the photomultiplier, the electron multiplier and the micro-channel plate detectors.

Drug Identification with Gas Chromatography Mass Spectrometry

Drug Identification with Gas Chromatography Mass Spectrometry Drugs is used everyday by people in many different ways for many different reasons. Drug testing has become a standard in pre-employment testing because of the wide variety of drugs used in society nowadays. Drugs tested for by a possible employer include Cocaine, Amphetamines, Opiates (codeine, morphine, and heroin), PCP (phencyclidine), and Marijuana. Gas chromatography/mass spectrometry is used to test hair and urine samples of possible drug abusers or job applicants, and it is the best method for the testing of drug use. Gas chromatography and mass spectrometry are two different methods for identifying chemical substances, and the two instruments have be coupled together to perform a highly complementary analytical function. The gas chromatograph and the mass spectrometer have theories behind how their techniques work, and specific forensic applications for their instrumentation. The gas chromatograph offers rapid and very high-resolution separations of a very wide range of compounds, with the only restriction that the analyzed substance needs to have sufficient volatility. The theory behind the mass spectrometer is to use the difference in mass-to-charge ratio (m/e) of ionized atoms or molecules to separate them from each other. Mass spectrometry is therefore useful for quantitation of atoms or molecules and also for determining chemical and structural information about molecules. Molecules have distinctive fragmentation patterns that provide structural information to identify structural components. The combination of the gas chromatograph and mass spectrometer is very easy, because both instrument needs to be modified in excess and both are analyzed in the gas phase and have comparable sample levels and temperature ranges. The most important feature of the two instruments being coupled is that they perform complementary analytical functions. The instrument’s parts include an injector, a carrier gas, a column, a separator, an ionization source, mass separator, and an ion detector. The injector is located on the gas chromatograph and is where the sample gas is injected into the instrument to start the process. The sample gas is then mixed with a carrier gas, which is the mobile phase in gas chromatography. The mixture proceeds into the capillary column where the separation of the sample begins. The capillary column is 15 to 60 meters in length and .25 to .75 millimetres in diameter. Once through the capillary column the now separated sample enters the separator. The separator connects the gas chromatograph with the mass spectrometer, and separates the carrier gas from the separated components of the mixture. The sample now enters the mass spectrometer’s ionization source where the sample molecules are fragmented and created into positively charged ions by high beam electrons. The fragmented positively charged ions now pass through the mass separator, which is a magnetic field. The mass separator isolates the fragmented sample into their masses. The isolated masses are read by an ion detector and then displayed as a mass chromatogram. A mass chromatograph is a graph of ion m/e abundance in relation to time. The gas chromatograph/mass spectrometer (GC/MS) produces a mass chromatogram of a substance that acts like a fingerprint for a chemical substance. The idea that a GC/MS produces a fingerprint for a chemical substance makes this instrument a convenient option when testing for drug identification and testing people for drug abuse. Forensic scientists find a drug’s identification by using a GC/MS, and use the mass chromatogram in comparison with the test results of another unknown mass chromatogram. If the two mass chromatograms match then the tested chemical substance is that drug it was matched against. Another application is using a GC/MS, and thereby testing hair or urine samples of people to determine if the subject to drug abuse. Drugs tested for might encompass such well-known drugs as Cocaine, Amphetamines, Opiates (codeine, morphine, heroin), PCP (phencyclidine), and Marijuana.

Gas chromatography/mass spectrometry is now considered the premier technique for separations and analysis of drugs. Employers will often test prospective employees for drug use. They test with the hair or urine samples of the prospective employee and run the sample through a GC/MS to determine if the possible employee has used drugs. They determine this by comparing mass chromatograms of known drugs with that of the test sample. The gas chromatograph/mass spectrometer is known as the best resource to prove the identification of a substance of abuse, because the mass chromatographs act like a fingerprint of a chemical.

Principle of Forensic Palynology

2008-09-12T22:23:00.000+05:30

Palynology is the branch of science dealing with study of pollens and spores (Webster,2008). The term palynology is derived from Greek word palynein meaning to sprinke and from
Forensic Palynology is the branch of Forensic Science which deals with the study of pollens and spores used in solving crimes.

Forensic Criminal Profiling from Crime Scene Analysis

2008-08-28T22:46:00.000+05:30

Even though Kim Rossmo (PhD Criminology) while working for the FBI is accreted for having devised the term Criminal Profiling in the early 1990s, there are recorded facts that the techniques were applied way back to the days of Jack the ripper (Ainsworth, 1995). As of today, there are contradictory reports as to who exactly developed criminal profiling. This is especially true when it comes to the FBI. There are more than one retired agents who worked for the FBI who claim sole responsibility for the development of many of the methods of criminal profiling in use today. It should therefore come as no surprise that profiling in one way, shape, or form was employed long before the Bureau even came into existence. (Picture courtesy J. D. Miller's Criminal Profiling)

For many years, the work of individual psychologists and psychiatrists could be described as profiling, in that they often provided advice to police agencies as to the type of perpetrator they were seeking, including their possible motivations for the crime. These kinds of recommendations are still produced today by many mental health practitioners on a need to know basis. It is therefore rare to find one psychologist or psychiatrist not employed in a law enforcement setting who only does profiling in their daily duties. The interpretations they make of criminal behaviour are usually the result of their knowledge of the human personality and of various psychological disorders. As a result, their interpretations tend to revolve heavily around personality and psychological anomalies.

Criminal profiling has come a long way since the time Dr. Thomas Bond performed an autopsy on Mary Kelly, the last victim of Jack the Ripper. He was engaged in a somewhat crude reconstruction of many aspects of the crime, possibly in an attempt to understand what occurred. He observed that the corner sheet to the right of the womans head was much cut and saturated with blood, indicating that the face may have been covered with a sheet at the time of the attack (Robertson, B & Vignaux, G. A., 1995). Observations made by Bond in the late 1880s were largely the interpretation of the Rippers behaviours at the crime scene, including the wound patterns inflicted upon the victim. He suggested that investigators look for a quite inoffensive looking man, probably middle aged and neatly dressed.

One aspect of the modern day profilers job is to examine a series of cases and advise as to whether there is a link between two or more cases based upon the crime scene and the victims. A similar approach was resorted by Dr. Bond stating that all of the victims had died by the by the same hand and that the same person did all the mutilations of Nichols, Chapman, Eddowes and Kelly (Ressler, 1985). This statement parallels what profilers refer to these days as a signature, or those behaviours or actions that fulfil a psychological or physical need of the offender.

As mentioned earlier, it is a common belief that the agents of the FBI developed the profiling process while working on serial crime investigations across the United States. In fact, the people who can be genuinely attributed with its development were using the practice long before these agents arrived at the bureau. Howard Teten began to develop his approach to profiling while working on the San Leandro, California Police Department. The staff at the School of Criminology provided Howards theoretical background for this. Later, when Teten became a Special Agent, he initiated his profiling programme in 1970, and compiled his first profile in Texas. He taught the first course at the FBI National Academy, entitled Applied Criminology. He later teamed up with Pat Mullany. It was not until some years later that the now widely known names of John Douglas and Robert Ressler came to the Behavioural Science Unit (BSU) (Cassey-Owens, 1984).

BSU undertook a large study in which they entered into correctional facilities and interviewed offenders about their backgrounds, crimes, crime scenes and victims. Court transcripts and other official sources of information including police reports and psychiatric and criminal records were also taken into consideration. The data collected served as the basis for the profiling method they developed and are still in use in many jurisdictions around the world.

Profiling does not provide specific identity of the offender. Rather, it indicates the kind of person most likely to have committed a crime by focusing on certain behavioural and personality characteristics. Law enforcement officers need to learn as much as possible about the offender, either by verbal contact or if possible, by access to his family and friends. The objective here is to try and learn the most likely course of action he is likely to take and what his reactions to various stimuli might be. Criminal profiling is a very diverse field. It can vary from extortion, to hostage situation, rape, fraud, theft or even violent crimes that would include homicide. The need for a systematic criminal enquiry cannot be overemphasised. Studies conducted around the world have shown that it is much less of a problem to solve a crime by grouping together similar or related incidents. Further progress in dealing with the problem requires rhe systematic collection and analysis of information about the incident. These would include not just the offenders, victims and those who may be involved, but also the time of occurrence, locations, and other particulars about the physical environment. Besides, the history of the problem, the motivations, gains, and losses of all involved parties, the apparent causes and competing analysis and to expand beyond the current limited objectives is imperative in the advanced crime analysis models.

Criminal profiling has been described as a collection of leads (Rossi, 1982), as an educated attempt to provide specific information about a certain type of suspect (Geberth, 1981), and as a biographical sketch of behavioural patterns, trends, and tendencies (Vorpagel, 1982). Geberth has also described the profiling process as particularly useful when the criminal has demonstrated some form of psychopathology.

As FBI describes it, the criminal profile generating process is defined as a technique for identifying the major personality and behavioural characteristics of an individual based upon an analysis of the crimes he or she has committed. The profilers skill is in recognising the crime scene dynamics that link various personality types who commit similar crimes. The process used by an investigative profiler is developing a criminal profile which is in a way similar to that used by clinicians to make a diagnosis and treatment plan: collection and assessment of data, reconstructing the data, formulating a hypothesis, developing and testing the hypothetical data, and finally reporting the results back. All this brainstorming also involves to an extent, intuition and educated guesswork. The expertise obviously does not come overnight but rather requires years of accumulated wisdom, extensive know-how in the field and familiarity with a significant number of cases. The formulation a forensic expert brings to the investigation is more often than not based on his/her previous experience in the field. Formulation here is defined as a concept that organises explains or makes investigative sense out of information and that influences the profile hypotheses. These formulations are based on clusters of information emerging from the crime scene data and from the investigators experience in understanding criminal actions (Rossi, 1982)

The FBIs Crime Scene Analysis has formulated a six step programme that is followed in a step by step manner to identify criminal profile, which is more or less set as a benchmark for most countries. These include:

Profiling Inputs
Decision Process Models
Crime Assessment
The Criminal Profile
The Investigation
The Apprehension

Profiling inputs stage begins with the criminal-profile-generating process. This requires a comprehensive case material collection for accurate profiling. For example, in a homicide case, the required information includes a complete synopsis of the crime and a description of the crime scene, encompassing factors indigenous to that area to the time of the incident such as weather conditions and the political and social environment (Reiser, 1992). Forensic profiling pertaining to the crime is also critical to the profiling process, including an autopsy report with toxicology /serology results, autopsy photographs, and photographs of the cleansed wounds. Complete background information on the victim is also vital in homicide profiles; the data should cover domestic setting, employment, personality, criminal record etc. The data and photographs can reveal significant elements such as the level of risk of the victim, the degree of control exhibited by the offender, the offenders emotional state and his level of criminal sophistication.

The decision process begins with the organisation and arrangement of the inputs received into a logical and coherent pattern. This would also include establishing how many victims were involved and under what circumstances; for example, with the purpose of establishing whether the crime was the result of a serial offender. If random murders were committed in different parts of a city over a period of time, though seemingly unrelated, it is only by the decision process through forensic evidence and analysis that this can be correlated.

Crime assessment typically involves the process of reconstruction of the sequence of events and the specific behaviours of both the victim and perpetrator (Reiser, 1992). This helps aid the analyst in understanding the role each individual has in the crime and should assist in developing the subsequent profile of the criminal. The classification of the crime is determined through the decision process outlined in the first decision process model. The classification of a crime as organized or disorganized was first introduced as classification of Lust murder (Hazelwood & Douglas,1980), but since has broadly expanded, includes victim selection, strategies to control the victim, and sequence of the crime. Organised murderer is one who appears to plan his murders, targets his victims, displays control at the crime scene and act out a violent fantasy against the victim. In contrasts, the disorganized murderer is less apt to plan his crime in detail, obtains victims by chance, and behaves haphazardly during the crime.

The fourth stage in generating a criminal profile involves with the type of person who committed the crime and that individuals behavioural organization with relation to the crime. Having generated the description, the strategy of investigation can be formulated. Included in the criminal profile are the demographics, physical characteristics, habits, beliefs and values, pre-offence behaviour leading to the crime, and post-offence behaviour. It is of vital importance if validating the criminal profile. It must fit with the earlier reconstruction of the crime with the evidence and with the key decision process models. In addition, the investigative procedure developed from the recommendations must make sense in terms of the expected response patterns of the offender. If there is a lack of congruence, the investigative profilers must review all the available data.

Once the analogy of the criminal profile is determined, a written report is provided to the requesting agency and added to its ongoing investigative efforts. Recommendations generated during criminal profiling are applied and suspects matching the profile are evaluated. Unless authenticated, the entire information has to be re-examined and the profile revalidated.

Finally, when the suspect is apprehended, the agreement between the outcome and the various stages in the profile-generating-process are examined. It is important to conduct a detailed interview to check the total profiling process for validity.

Besides the efforts put in to improve the profiling techniques, there has been a lot of widespread criticism. The primary foundation of the FBIs system lies within the organised offender Disorganised dichotomy. It is argued that federal agencies have little experience in actually investigating murder cases, and that it would be better for local agencies to train their own officers in the intricacies of such investigations. Despite these criticisms, the methods employed by FBI remain one of the most widely taught criminal profiling techniques in the world today. Agents from various countries around the world travel here to take part in the Bureaus Fellowship Programme.

Dr. David Canter, Director of Centre for Investigative psychology (Liverpool) has employed methods similar to those of the FBI in that both are largely statistical in nature. The main difference is that Canter is continually updating his database of offender populations on which to base his theories. This subsequently produces a list of characteristics likely to be possessed by the unknown offender by virtue of their similarity to the comparison (or known) offender group. Canter has also developed a model of offender behaviour known as the circle theory, which is based directly upon environmental psychology. Two models of offender behaviour known as the marauder and commuter hypothesis were developed from the circle theory. The former assumes that an offender will strike out from their home base in the commission of their crimes, whereas the commuter model assumes that an offender will travel a distance from their home base before engaging in criminal activity. Very little data however is available to tell the practitioner how to apply this model to an actual investigation.

The latest method of those presented in this work is that developed by Brent Turvey, a forensic scientist and private criminal investigator. He was able to compare
the established and documented actions of the perpetrator with the verbal reports provided by the perpetrator. This took into account things such as the fact that offenders will lie about their actions, and that sometimes the most objective record of what happened in a criminal event is a reconstruction of offender behaviour. Hence, Behavioural Evidence Analysis (BEA) was developed.

Since BEA does not use a statistical reference group from which to create a criminal profile, it may be considered as the method with the greatest cross cultural applicability when assessing criminal behaviour. It is a robust method which takes into account all of the physical evidence left behind at a crime scene, the offender behaviour and the victim characteristics, which collectively produce the profile of the individual responsible. Perhaps the biggest drawback here is that it is extremely time consuming.

Criminal personality profiling has proven to be a useful tool to law enforcement in solving violent and apparently motiveless crimes. The process has aided significantly in the solution of many cases over the past decade. It is believed that through the research efforts of different branches of forensic sciences and professionals in other fields, the profiling process will continue to be refined and be a viable investigative aid to law enforcement. The importance of criminal profiling always strikes a chord within practitioners, a resonance best explained by an old police truism: When all else fails, return to the scene (Barrettt, 1990).

Investigation of a Crime Scene

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Initial Response and Prioritization:

Investigators approached the crime scene securing the crime scene to preserve the scene with minimal contamination and disturbance of physical evidence. The initial responding officer(s) should be prompt, yet cautious in their approach while entering the compound, remaining observant of any persons, vehicles, events, potential evidence, and the environmental conditions. The entire area should be thoroughly assessed and any possible secondary crime scenes should be ruled out. Observations relating to any persons and vehicles in the vicinity that may be related to the crime must be made. This is always done because the protocol states that while entering a crime scene, one is expected to assume that the crime is still ongoing unless proved otherwise. The control of potential physical threats is to ensure the safety of officers and others present. After the initial observations are made and officer safety is ensured, all the initial details are recorded in a log book.

Once this is done, the initial responding officer assesses the victims for any sign of life and the medical personnel are immediately called for. The same are guided to the crime scene after instructing them to minimize contact so as to prevent alteration or contamination of the crime scene. They are also instructed to take a ‘dying declaration’ if a critically injured person has a high probability of not surviving to the hospital.

Securing the crime scene:

The primary aim after removal of injured persons is to protect the integrity of the crime scene. Controlling, identifying, and removing persons at the crime scene and limiting the number of persons who enter the crime scene and the movement of such persons is the most imperative primary task. The initial response officer is responsible for controlling all individuals at the crime scene and preventing them from altering or destroying any evidence at the crime scene. Nothing should be removed from the crime scene initially unless absolutely necessary. The crime scene should remain as close as possible to its original condition when the investigating officers arrive. If removal of an object is absolutely essential, then it should be handled with proper care, for it might contain fingerprints or other vital clues that might aid the case (Faigman, D.L. et al., 2002).

The officer is expected to establish boundaries starting from the focal point and extending outwards. An ample area should be roped off, so that the path taken by everybody involved to and from the crime scene proper is covered. Thus the barricades should be sufficiently extensive. Once this has been done, physical barriers using crime scene barrier tape is set up. No smoking, eating or drinking is allowed. A single point of entry and exit is set-up for any person entering or exiting the scene. The first thing the investigator does then is a ‘walk through’ for initial assessment. The protection of the scene in this case is so that nobody else walks around aimlessly inside the cordoned area, or immediately outside the roped off area (Henry C. Lee, Timothy M. Palmbach, Marilyn T. Miller, 2001). This limited movement permits later accountability of the officer’s own tracks at the crime scene. The overall crime scene security is divided into multilevel security areas (DeForest, P., Gaensslen, R., 1993). These are:

Level 1- Overall scene security (restriction of general public and media).
Level 2- Restriction to official business and the temporary command centre.
Level 3- Target area with the highest security.

The protective measures should be taken as soon as possible so as to avoid loss of vital evidence. At no time should the first officer at the crime scene leave the area under the supervision of others.

Initial Management at the scene of crime:

If the first officer establishes the certain signs of death like rigor mortis, odour, early signs of putrefaction etc, a cursory inspection of the crime scene are mandatory. The superiors must be notified regarding the case. Until the investigator personals arrive, the officer should attend to the following:
1. Write names of witnesses and other persons who entered the scene. This helps in sorting of fingerprints and other clues.
2. Make a note of who was at the scene when the officer first arrived.
3. Establish the basic facts as far as possible, so that the next step in investigation can be determined.
4. Ensure that witnesses are kept separated as it can lead to discrepancy in each individual’s opinion.
5. Never discuss the crime with bystanders or witnesses.

A crime scene investigation is characterized by three essential factors for success: Organization, thoroughness, and caution. The approach to any crime scene investigation should be based on a systematic basis, with a formulation of a proper preparation on as to how to go about with the scene management. Initial assessment in any crime scene begins with documenting the scene (Fisher, 2004). This process includes:
(a) Photography/videotaping (overall views).
(b) The investigation of the crime scene proper.
(c) Sketching.
(d) Note taking (to be done throughout the investigation-constant interruption for notes are the rule). Well –written, contemporaneous notes are invaluable not only later in the investigation, but also during the trial.

Actual Examination of the crime scene:

Once a Forensic Expert has taken charge, he should be fully briefed of the information collected thus far. Investigators should not start the crime scene investigation of the dead body until the basic examination of the scene is completed. This is because vital facts may be discovered that are of value in relation to findings on the body. However, a preliminary inspection of the body to suggest mode of death can precede the crime scene search. It is always better to have more than one expert at the crime scene. They should be used to working on crime scenes together and be able to co-operate with each other. Where one might carry out the actual examination, the other should be taking notes.

An investigator is expected to assume what possibly might have occurred and reconstruct the scene. Following a systematic and thorough survey, reconstructing the scene involves two main questions the expert must determine: Why and How. The various stages of reconstruction involve the following:
Data collection.

Conjecture i.e. a possible explanation for the crime to have occurred.
Hypothesis formulation- This is based on the examination of physical evidence.

The reason that everything should always be written down is so that the same can be analysed later. The location and objects should be described in detail before they are moved from the site. The extent of notes is usually proportionate to the crime (Horvath, F., Meesig, R., 1996). There are instances when lots of inconsistencies are encountered at a crime scene. For example; in case of genocide there should some form of explanation as to why some of the deaths would occur at the compound while others elsewhere. In such a scenario, the best way to proceed is by method of elimination.

Leaving significant objects in their original position is perhaps the most popular technique employed during the investigation to aid in reconstructing the crime. One of the first things to do is put away things that would interfere with the scene investigation. These would include empty film packs, blood testing materials and other things an expert uses during investigation.

A temporary work station is then setup. It is here that all the collected evidence is tagged, casting material is handled and at times, fingerprinting is done (Horvath, F., Meesig, R., 1996). Special techniques need to be applied for detection, preservation and evaluation of evidence, depending on the evidence found. For example, blood pattern analysis, firearms and cartridges, recreational drugs etc.

Blood stain pattern analysis is useful to determine if the blood was that of human or bovine. The pattern also helps determine the type of weapon used (e.g. high velocity firearm, shotgun, blunt trauma, etc.), trajectory of a bullet, angle of impact, DNA analysis etc. These are a highly specialized and evolving fields used for homicide cases ( to be discussed later in individual posts).
In a situation where firearms and ammunition is used, the same should be left untouched until investigating personnel arrive. During recovery of weapons, the Investigating Officer (IO) should concentrate on the possibility that valuable evidence may be found on cartridge cases as well as on the weapons. The weapons recovered at an outdoor crime scene (esp. in cold weather), should not be moved to a heated room. This is because if any oil or grease is present on the weapon, there is a reasonable chance for fingerprints to be present on them, and this could be destroyed by the heating in the room (Fisher, 2004). A pistol or a revolver should never be picked by inserting a probe into the barrel (as seen in most high drama movies and television programmes!), for it might dislodge the dust or other debris in the barrel. Ideally this should be done by grasping the chequered surface of the grips with two fingers. Before lifting the firearm, its position should be marked on a sketch, photographed and its outlines be marked on the site of recovery. Ideally, a weapon recovered should be delivered in the same condition in which it was recovered to ballistics experts. It should be packaged; a detailed description of what was done to it may be prepared and sent to the crime library. The only acceptable change to the weapon would be to remove a cartridge from the chamber, which should only be done by a person with firearms experience (Norby, J., 2000).

As soon as the IO has completed the crime scene examination, a Forensic Pathologist is almost always called to a Homicide Scene of Crime.. It is the pathologist’s duty to identify the deceased, determine time since death, and take custody of the remains. Ideally, the forensic pathologist or the coroner conducts the initial examination at the crime scene itself (Fisher, 2004). After getting the consent from the coroner/pathologist, the attending police officer calls upon the contractor for the transportation of the bodies to the nearest hospital mortuary.

A scientific approach to crime scene investigation is the best methodology to ensure that an investigation is properly conducted and justice is served. Use of these above mentioned techniques ensures prevention of an abrupt end of an incomplete investigation and allows for the best use of the physical evidence found at the crime scene.