Archive for the ‘Crime Scenes’ Category


Identifying the Dead: Forensic Science and Human Identification online course

Wednesday, August 12th, 2015

Uncover a grave, examine remains and reveal the victim’s identity in this free online course, linked to a new Val McDermid story, that is being offered through by the University of Dundee.

Starting date: 7th of September 2015
Duration of course: 6-weeks
To register: Please visit

About the course

The first step in any investigation involving a death is to determine the identity of the deceased. This free online course will take you on a journey through the world of forensic anthropology, unveiling the tools that will allow you to reveal that identity.

Join forensic experts to identify the dead

In the shadow of Dundee’s Law Hill, a grim discovery demands the attention of forensic experts. Unidentified human remains have been found and the police need to identify the victim to move forward with their investigation.

After a meticulous recovery of the remains, it will be your job to:

  • document and attempt to explain any evidence of trauma;
  • identify the victim through biological profiling;
  • and undertake a facial reconstruction.

Experts from the University of Dundee’s award-winning Centre for Anatomy and Human Identification (CAHId) will guide you through the process of human identification.

They will introduce you to the fields of human identification; forensic anthropology and archaeology; craniofacial identification; and the study of the human body.

Evaluate evidence as the case unfolds

Week-by-week, the case will unfold, providing you with more information about the victim. You will be presented with theoretical material and hands-on learning opportunities, to evaluate the case information and use what you have learned, to piece together clues to the victim’s identity.

You will be able to discuss, with educators and others learners, your thoughts on the identity of the deceased, based on your evaluation of the evidence.

Get your own copy of the murder mystery

After you submit your evaluation of the victim’s identity, all will be revealed at the end of the final week. You can continue your journey into the life and death of our victim in your very own ebook copy of a specially-written murder mystery by international best-selling crime novelist Val McDermid.


No special knowledge or previous experience of studying is required.

Specialist police sniffer dogs lead to 215 arrests

Monday, June 29th, 2015

As long as crime has been fought, dogs have been used in the battle to keep lawlessness at bay. But mention a police dog and thoughts inevitably turn to that of a dog with its teeth bared, chasing down a criminal or keeping angry protesters at bay during riot control.

However, there is an elite group of 30 dogs in South Africa that never bare their teeth, and are usually friendly Border Collies or Labradors.

These are the dogs known as the biological, body fluid detection canines. They are specialised in detecting blood and semen. It is this ability that helps detectives solve crimes or gather vital evidence, especially in murder and rape cases.

National police spokesperson Brigadier Vishnu Naidoo said in the year ended March 2015, these specialist canines were involved in almost 2 300 searches with 706 samples of blood or semen found and 215 suspects arrested.

There is one such dog at the Umzinto Dog Unit on the KwaZulu-Natal south coast. Paris loves nothing more than to chase down a tennis ball and bring it back to her handler, Warrant Officer Jason Reddy. However, the moment he puts her harness on, it is time to work seeking out blood or semen that is not readily visible.

K9 unit

What kind of dog is recruited to help the detectives?

“It has to be a dog with a friendly disposition. It also needs to be a dog that can get into small areas,” says Reddy, a 20-year veteran of the police. At least 18 of those years have been with the police dogs, or the K9 unit, as it is more commonly known.

Border Collies, Labradors and on occasion German Shepherd dogs are used. Paris is a black and white Border Collie with a little more than five years of service and, according to Reddy, has been the crucial link in a number of cases that have resulted in convictions.

In one case in which two girls were raped in Hibberdene on the KwaZulu-Natal south coast, Paris found a drop of blood that was not seen by the naked eye. The sample was taken and tested. The DNA from that small drop matched the DNA of a suspect already on the police’s database.

“That suspect had a previous conviction and we had his DNA on our database. He got 25 years,” said Reddy.

Paris has been trained to differentiate between human and animal samples. She can smell a pinprick-size sample of blood that is not visible to the human eye and can smell blood even if it has been washed away.

In a case where three people were killed in a hit-and-run accident, it was Paris’s sharp smelling ability that picked up the trace of blood inside a hole that would normally contain a screw holding the mud flap of the car that clinched the case. The driver, whom police suspected, had washed the car. The blood found by Paris was tested and found to belong to one of the three dead girls. Her sharp nose saw to it that the driver was convicted of culpable homicide.


The dogs like Paris are picked once they are at least 14 months old and then undergo training at the police’s K9 Dog Training Academy in Roodeplaat in Pretoria.

Captain Cliffie Pillay, who is responsible for the police’s canines in KwaZulu-Natal, said the handlers of biological, body fluid detection canines must have had at least two years of experience as a dog handler.

Reddy was previously the handler of a dog trained to seek out explosives. And before he was teamed up with Paris, he too had to undergo training.

Reddy and Paris get called out once a day by detectives for murder cases or by the Family, Violence, Child Protection and Sexual Offences Unit for rape cases.

In fact it was such a dog that was called out to help police last week in the hunt for two men who are alleged to have raped an American tourist in the Tsitsikamma National Park.

In one case where a couple was arrested for stabbing Umzinto grandmother Sushila Pillay, Paris located the alleged murder weapon – a knife – in the Umzinto River a week after the murder.

In Durban’s western suburb of Malvern, police had caught the suspect who had told them where he had thrown the knife used to stab a man. Officers could not find it in the open patch of land, but Paris found it still with the victim’s blood on it. While not necessary for the conviction, it solidified the case the police had against the man.

99% success rate

A quiet “Soek” from Reddy sends Paris looking for blood or semen, depending on what is required. When she finds it, she sits down at the spot. And that is when the forensics experts move in to confirm her good work and extract samples required for DNA testing.

In another case a woman who was raped repeatedly in a forest in Dududu near Umzinto was so distraught that she could not recall where in the forest the crime had occurred.

Reddy and Paris were called in and five different crime scenes in the forest were located by Paris.

Paris is expected to work for another five years at least, but even she is tested annually by Pillay to ensure that she is up to scratch.

According to Pillay, Paris will find that sample of blood or semen more than 99% of the time.

There are currently only two biological, body fluid detection canines working in KwaZulu-Natal, but according to Pillay there are plans to bring more of dogs like Paris to KwaZulu-Natal, so criminals beware.

This article was first published by on 21 June 2015

What is Forensic Photography?

Tuesday, June 9th, 2015

Put simply, forensic photography (also known as forensic imaging or crime scene photography) relates to photography that is undertaken within a legal context, for example; providing an accurate visual record of an accident or crime scene.

In the process of aiding an investigation and/or legal proceedings in court, forensic photographers are called upon to photograph a wide range of subjects.

These include:

  • Crime Scenes
  • Gunshot Wounds
  • Bitemarks
  • Weapons
  • Trace Evidence
  • Autopsy Procedures

Less obvious but equally important photographic protocols include taking pictures of mail and newspapers to help establish date of death and photographs taken from the perspective of witnesses at the time of the crime etc.

The following short documentary by David Beazley takes a fascinating look at Forensic Photography through the eyes of Nick Marsh – a forensic photographer of over 20 years.


Forensic Photography

The Forensic Photographer

Crime scene discovery – separating the DNA of identical twins

Monday, May 11th, 2015

Forensic scientist Dr Graham Williams uncovers one of the DNA’s longstanding mysteries

SINCE its first use in the 1980s – a breakthrough dramatised in recent [UK] ITV series Code of a Killer – DNA profiling has been a vital tool for forensic investigators.  Now researchers at the University of Huddersfield have solved one of its few limitations by successfully testing a technique for distinguishing between the DNA – or genetic fingerprint – of identical twins.

The probability of a DNA match between two unrelated individuals is about one in a billion.  For two full siblings, the probability drops to one-in-10,000.  But identical twins present exactly the same DNA profile as each other and this has created legal conundrums when it was not possible to tell which of the pair was guilty or innocent of a crime.  This has led to prosecutions being dropped, rather than run the risk of convicting the wrong twin.

Now Dr Graham Williams and his Forensic Genetics Research Group at the University of Huddersfield have developed a solution to the problem and published their findings in the journal Analytical Biochemistry.

Previous methods have been proposed for distinguishing the DNA of twins.  One is termed “mutation analysis”, where the whole genome of both twins is sequenced to identify mutations that might have occurred to one of them.

“If such a mutation is identified at a particular location in the twin, then that same particular mutation can be specifically searched for in the crime scene sample.  However, this is very expensive and time-consuming and is unlikely to be paid for by cash-strapped police forces,” according to Dr Williams, who has shown that a cheaper, quicker technique is available.

Dr Graham Williams

It is based on the concept of DNA methylation, which is effectively the molecular mechanism that turns various genes on and off.

As twins get older, the degree of difference between them grows as they are subjected to increasingly different environments.  For example, one might take up smoking, or one might have a job outdoors and the other a desk job.  This will cause changes in the methylation status of the DNA.

In order to carry our speedy, inexpensive analysis of this, Dr Williams and his team propose a technique named “high resolution melt curve analysis” (HRMA).

“What HRMA does is to subject the DNA to increasingly high temperatures until the hydrogen bonds break, known as the melting temperature.  The more hydrogen bonds that are present in the DNA, the higher the temperature required to melt them,” explains Dr Williams.

“Consequently, if one DNA sequence is more methylated than the other, then the melting temperatures of the two samples will differ – a difference that can be measured, and which will establish the difference between two identical twins.”

Pictured (left to right) are Dr Williams's students Dieudonné van der Meer, Leander Stewart, Neil Evans and Kimberley Bexon.

HRMA has some limitations, acknowledges Dr Williams.  For example young twins, or twins raised in highly similar environments may not have yet developed sufficient methylation differences.

Also the technique requires a high sample quantity that might not be present at the crime scene.

“Nevertheless, we have demonstrated substantial progress towards a relatively cheap and quick test for differentiating between identical twins in forensic case work,” says Dr Williams, who gives a detailed summary of the science behind the breakthrough at blog-site The Conversation.

SOURCE: This article was first published online by the University of Huddersfield on 20 April 2015.

Infographic: What are DNA profiles used for?

Monday, May 4th, 2015

Thanks to SciBraai and Anina Mumm for sharing this infographic with us.

DNA profiling has revolutionised criminal justice globally and in South Africa. The graphic below was created in 2012, to accompany a feature on the potential promise and pitfalls of a DNA database as set out in the then ‘DNA Bill’.


Excavating a grave site: Anthropological or forensic crime scene?

Friday, April 24th, 2015

A skeleton appearing in a grave.

Following the recent discovery of mass graves on Glenroy farm in Dududu (KZN) some months ago, the question arose as to whether the scene should be handled as a forensic (crime scene) or anthropological/archaeological case.

While a commission of inquiry has been established, it is being treated as forensic case in the first instance until otherwise determined and as such currently falls under the jurisdiction of the SAPS forensics unit while they conduct their preliminary investigations.

But what exactly is the difference between a forensic and an anthropological/archaeological case when investigating human remains?

In a forensic case the responsibility for the investigation of deaths due to unnatural causes lies with the Forensic Pathology Service in the province where the incident occurred and under the Inquests Act (Act 58 of 1959), this Service makes provision for the rendering of medico-legal investigation of the cause of death and serves the judicial process.

Up until 2006 this function was performed by, and fell under, the SAPS. As stipulated by the National Health Act (Act 61 of 2003), the operational management of the medico-legal laboratory facilities was subsequently transferred to the different provincial Departments of Health.

In an anthropological case, jurisdiction over inadvertently discovered human remains is governed by the National Heritage Resources Act (Act 25 of 1999) which stipulates that all discoveries of human remains should be reported to the local SAPS and the relevant Heritage Resources Agency.

Human remains identified by the Act, or proclaimed by the minister of Arts and Culture, should be reported to the South African Heritage Resources Agency Burial Grounds and Graves Unit. Jurisdiction, that is, whether the remains are forensic in nature or of heritage value, and whether the cause of death was non-natural and judicially relevant, is then assigned after consultation between officials.

As a general rule, although specified exceptions to this are indicated in the National Heritage Resources Act, human remains older than 60 years are not forensic, and remains older than 100 years are considered to be archaeological.

The National Heritage Resources Act also identifies categories of human remains, such as Victims of Conflict (referring to victims of the pre-1994 political violence in South Africa), which are classified as human rights abuses and deserving of special investigation and commemoration.

What is forensic anthropology?

Forensic anthropology is a specialist field that deals with the evidence that can be collected from human remains – both hard tissue in the form of dry bones and soft tissue in the form of dried flesh from dried up or mummified bodies.

A forensic anthropologist has detailed knowledge of anatomy, particularly the anatomy of the human skeleton, since the bones are usually all that remains when a forensic anthropologist is called in to identify a body.

What is a forensic anthropologist able to discern in respect of discovered remains that will aid the investigation?

Forensic anthropologists are able to reconstruct information surrounding the events that lead to the preservation of the discovered remains and call this the study of ‘taphonomy’, which includes the evidence of death, and the accumulation and preservation of bones over time.

Forensic anthropologists speak of four taphonomic periods in relation to a dead individual:

  • the ante-mortem period, which covers the whole of the time before the death of the person
  • the peri-mortem period, which is around the time of death
  • the post-mortem period which includes the time between death and discovery
  • the post-recovery period which includes the process of recovery, analysis and storage of the bony evidence.

Each period provides different contexts for enquiry. During the ante-mortem period (before death), the skeleton is living and records its own details of growth and development.

These can be used to develop a biological profile of the individual and help in securing identification.

The peri-mortem period is obviously important because it includes the events around the death and the cause of death.

However, the post-mortem period is important as well because it gives the time context of the crime by revealing information about the post-mortem interval (PMI). Each and every event after the discovery needs to be recorded as part of the ‘chain of custody’ so that there are no questions about the data when the case is discussed in court.

How can forensic anthropologists estimate sex and age?

By examining the skeletal remains, an anthropologist can estimate whether they are from a male or female.

A skeleton’s overall size and sturdiness give some clues. Within the same population, males tend to have larger, more robust bones and joint surfaces, and more bone development at muscle attachment sites.

Pelvic differences between males and females.

However, the pelvis is the best sex-related skeletal indicator, because of distinct features adapted for childbearing.

The skull also has features that can indicate sex, though slightly less reliably.

Male skull

Female skull

Determining how old a person was when they died is much more difficult than estimating their sex. The estimation of age at death involves observing morphological changes (changes in structure) in the skeletal remains and comparing it to what is known about chronological changes (changes that happen as we get older) that occur in the skeleton.


Friedling, J. (2012). What the bones can tell us. QUEST, 8(2). Academy of Science for South Africa.

Groen,W.J.M.,  Márquez-Grant, N., Janaway, R. (2015). Forensic Archaeology: A Global Perspective. Wiley-Blackwell.

Morris, A. (2012). What is forensic anthropology? QUEST, 8(2). Academy of Science for South Africa.

DNA Test That Distinguishes Identical Twins May Be Used in Court for First Time

Tuesday, December 16th, 2014

In 2004, two young women were abducted at gunpoint while walking home near Boston [United States] at night. The crimes happened eight days apart, but the pattern was the same: The women were shoved into a car by two men, pistol-whipped, driven to a different location, and raped. While collecting her clothes, the second victim managed to grab the condom one of the men had worn; she hid it in her pocket, and turned it in as evidence.

One of the two men involved pleaded guilty to the attacks in 2012. The other remained at large. Police had a suspect, but they couldn’t pin the crime on him due to a twist of genetic fate: He had an identical twin brother, and DNA from the condom matched both siblings. But now, a decade after the assaults, scientists have developed a genetic test that can distinguish between identical twins, and it may be used in court for the first time in this case.

The second suspect is 33-year-old Dwayne McNair. In September, McNair was arraigned on eight counts of aggravated rape and two counts of armed robbery, stemming from the two sexual assaults.

Traditional forensic methods can’t differentiate between DNA belonging to identical twins

He’s been a suspect in the crimes since 2007. According to court documents, a standard genetic test linked him to semen collected from the second attack back in 2008. That would ordinarily be enough to justify charges, but Dwayne wasn’t the only person whose DNA matched that semen. His twin, Dwight, was also a match. Traditional forensic methods can’t differentiate between DNA belonging to identical twins, and without a clear way to establish whether Dwayne or Dwight had left the semen at the scene, police had no probable cause to make an arrest in 2008.

But in 2012, the other man involved in the assaults told investigators that Dwayne had been his partner in the crimes. And earlier this year, prosecutors learned of a new forensic genetics test claiming to differentiate between biological samples belonging to identical twins. According to the Suffolk County District Attorney the test points to Dwayne, not Dwight, as the perpetrator of the 2004 assaults.

Normally, forensic tests work by extracting and amplifying regions of DNA collected from a crime scene. Then, investigators look for a match between the evidence and a suspect’s genetic sequence. Ordinarily, this kind of testing is sufficient: Most humans vary from one another enough for investigators to easily identify whether a suspect left blood, skin, hair, semen, or something else at a crime scene.

This is not true with identical twins. Grown from the same, single fertilized egg, monozygotic twins have nearly identical genomes. So, for decades, twins committing crimes had a relatively easy way to establish doubt—based on DNA evidence alone, their identical sibling would be equally as likely to have deposited whatever genetic material might have been left at a crime scene.

Maybe not anymore.

Using what’s known as ultra-deep, next-generation sequencing, a team in Germany has developed a test that claims to reliably identify which twin a biological sample belongs to. The test works by taking a close look at the genetic letters (called base pairs) comprising the 3 billion-base-pair human genome. Because mutations randomly occur during development, even genetically “identical” twins will vary at a handful of locations, says Burkhard Rolf, a forensic scientist at Eurofins Scientific, the company that developed the test.

The sequence mutations are random, so it’s incredibly unlikely they’d be the same in both twins—and it’s those discrepancies that can be used to pin a crime on a twin.

In a proof-of-principle study, Rolf and his colleagues analyzed sequences from a pair of twins and one of their kids. Scientists could positively identify which twin was the child’s father, based on five single base pair differences present in the father and son, but not in the uncle. They published the work earlier this year in Forensic Science International: Genetics; it’s this paper that caught the Suffolk District Attorney’s attention.

Results from Eurofins, showing one of the mutations

The office sent evidence to Eurofins for analysis. After the results came back, the McNair was indicted and arraigned for the crimes in September.

“At arraignment, the assigned prosecutor cited the Eurofins test results and said Dwayne McNair was ‘two billion times more likely’ than his twin to have been the source of the crime scene DNA,” says Suffolk DA spokesperson Jake Wark.

Now, the question is: Will the genetic test be admissible in court? It would be the first time it’s been used in the United States. A preliminary hearing has been scheduled for Jan. 12, 2015, after which a judge will decide whether evidence from the test is admissible.

Some experts seem to think it will hold up.

“It is scientifically sound and reliable, has a high probability of success, is based on standard, generally accepted forensic DNA sequencing technology, and has an infinitesimally low risk of error if proper laboratory practices are followed,” said Bruce Budowle, in an affidavit to the court. Budowle, who is now at the University of North Texas Health Science Center, once led the FBI’s DNA typing laboratory.

Yet some scientists are a bit wary. “I think it’s an interesting idea,” says computational biologist Yaniv Erlich of the Massachusetts Institute of Technology. The work published by the Eurofins team is accurate, he says, but is only based on one pair of twins. In an ideal world, Erlich would test the method using dozens of twin pairs, while simulating the small amounts of DNA that might be found at crime scenes.

He’s also concerned about the test’s applicability to different tissue types, and blood in particular (which is not an issue in the McNair case). In 2011, Erlich took a close look at the blood of identical twins who shared a placenta during development; early on, these twins are also sharing blood – even as adults, each twin has blood cells with DNA from the other twin.

“Think about one twin being Coca-Cola, the other twin is Sprite,” Erlich said. Their blood will be a mix of Coke and Sprite. “It’s not 50-50,” he said, “but it could be 20-80.”

In other words, while the Eurofins method might not work as well with blood samples left at crime scenes. But when it comes to saliva, skin, or semen, it could mean that identical twins are about to lose their genetic get-out-of-jail-free card.

SOURCE: This article was first published by Wired on 4 December 2014 and written by Nadia Drake –

Operation: SC@T!

Monday, December 8th, 2014

SC@T means “Securing a Crime scene @ Traffic incidents”.

On June 2nd, the DNA Project launched the first of several sessions at the Gene Louw Traffic Training College in Brackenfell, Cape Town. Operation SC@T had been specially designed to combine Crime Scene Awareness concepts and actions with the activities of Traffic Officers.

Increasingly, traffic incident scenes (TIS) are found to have an underlying criminal basis – these include crimes such as motor vehicle theft (MVT), hijacking, sexual assault and human trafficking, among others.

SC@T workshop in action with Dr Rebello.

One hundred and forty two (142) experienced and trainee officers who work in the Cape Town area attended the interactive sessions.

Officers were told that it is virtually impossible to not leave evidence at a crime scene. Often the evidence is in a biological form and therefore not “obvious”.

Examples of evidence items include clothing, cigarette ends, chewing gums, empty bottles and papers found in the vehicle.  These common items contain DNA from skin cells, blood, hair and saliva cells left there by the victim and perpetrator(s).

The take-home message for the officers was clear:  DNA CSI

Traffic officers testing their knowledge in an interactive Q&A session.

DDo not touch!

NNote and Record

AAssist others

C Careful! Contamination!

S SC@T – secure the crime scene

IInsist no-one interferes

In recognition of “SECURING the crime scene”, there were discussions on the practical aspects of doing this.  Following an assessment at the end of each session, the Officers were each given a “goody-bag” containing a certificate, a lanyard and glossy information booklet.

Dr Renate Rebello - Western Cape Trainer

NOTE: If you wish would like to book one of our new SC@T workshops for your Traffic Department or College, please contact our National Co-ordinator Maya Moodley at

What Happens to a Dead Body in the Ocean?

Thursday, October 30th, 2014

Deep-sea scavengers made quick work of this pig's carcass. Credit: VENUS/Gail Anderson and Lynne Bell

When a dead body decomposes in the ocean, scientists know little about what happens to it. To find out, some researchers performed an unusual experiment that involved dropping pig carcasses into the sea and watching them on video.

Lots of human bodies end up in the sea, whether due to accidents, suicides or from being intentionally dumped there, but nobody really knows what happens to them, said Gail Anderson, a forensic entomologist at Simon Fraser University in Canada who led the unusual study.

Anderson and her team got a chance to find out, using the Victoria Experimental Network Under the Sea (VENUS), an underwater laboratory that allows scientists to take video and other measurements via the Internet. With that equipment, all they needed was a body. [See Video of Ocean Scavengers Eating the Dead Pigs]

“Pigs are the best models for humans,” Anderson told Live Science. They’re roughly the right size for a human body; they have the same kind of gut bacteria, and they’re relatively hairless, she said.

In the study, published Oct. 20 in the journal PLOS ONE, Anderson and her team used a remotely operated submarine to drop three pig carcasses into the Saanich Inlet, a body of salt water near Vancouver Island, British Columbia, at a depth of 330 feet (100 meters).

The researchers monitored what happened to the pig bodies using the live VENUS cameras, which they could control from anywhere with an Internet connection, and sensors that could measure oxygen levels, temperature, pressure, salinity and other factors. At the end of the study, the scientists collected the bones for further examination.

It didn’t take long for scavengers to find the pigs. Shrimp, Dungeness crabs and squat lobsters all arrived and started munching on the bodies; a shark even came to feed on one of the pig corpses. Scavengers ate the first two bodies down to the bones within a month, but they took months to pick the third one clean.

The third body likely took so much longer due to the levels of oxygen in the water, the researchers found.

The Saanich Inlet is a low-oxygen environment, and has no oxygen during some times of the year, Anderson said. When the researchers dropped the first two pigs into the water, the oxygen levels were about the same, but when scientists dropped the third body in, the levels were lower.

The big scavengers (Dungeness crab and shrimp) need more oxygen to smaller creatures like the squat lobsters. But the smaller animals’ mouths aren’t strong enough to break the skin of the pigs. So as long as the carcass entered the water when oxygen conditions were tolerable, the larger animals would feed, opening the bodies up for smaller critters and the squat lobsters, Anderson said. But when oxygen was low, the larger animals didn’t come, and the smaller animals couldn’t feed.

“Now we have a very good idea of how bodies break down underwater,” Anderson said. This kind of research helps solve mysteries such as the “floating feet” found wearing running shoes that have washed up along the West Coast in recent years. In fact, it’s quite normal for ocean scavengers to gnaw off feet, and the running shoes simply make the body parts float, Anderson said.

Knowing how bodies degrade in the ocean can give rescue divers a sense of what to look for, as well as manage the expectations of family members of those lost at sea, Anderson said.

SOURCE: This article was first published by Live Science on 28 October 2014 and written by Tanya Lewis –

What is Forensic Toxicology?

Thursday, October 2nd, 2014

The field of forensic science has come a long way – this is particularly true in the area of forensic toxicology, which is both fascinating and important for many applications. Forensic toxicology deals with the investigation of toxic substances, environmental chemicals or poisonous products. If you have ever been asked to take a drug test for work or you know someone who has, then you are already familiar with one of the applications of forensic toxicology. The toxicology part refers to the methods used to study these substances. Forensic toxicology is actually a bit of a mix of many other scientific disciplines such as chemistry, pathology and biochemistry. It also shares ties with some of the environmental sciences.

Using Forensic Toxicology Today

Forensic toxicologists perform toxicology screens, which involve looking for unusual chemicals in the body.

Currently, this area of forensics has evolved to mean the study of illegal drugs and legal ones such as alcohol. Forensic toxicology can even identify poisons and hazardous chemicals. The chemical makeup of each substance is studied and they are also identified from different sources such as urine or hair. Forensic toxicology deals with the way that substances are absorbed, distributed or eliminated in the body – the metabolism of substances. When learning about drugs and how they act in the body, forensic toxicology will study where the drug affects the body and how this occurs.

Obtaining Samples for Toxicology Testing

Before toxicology testing can go forward, samples need to be taken. You might be surprised to know just how many parts of your body can produce samples that are effective for identifying drugs. One example is urine, which is commonly used in forensic toxicology. It’s an easy sample to obtain and relatively rapid and non-invasive. It can show substances even several weeks after their ingestion. One example would be the drug marijuana, which can be detected even two weeks following use of the drug. When a urine sample is taken, however, there are sometimes rules and regulations around how the sample is collected. If the testing was related to workplace drug testing, a person could substitute a sample from someone else that would then show a negative result. For this reason, there are sometimes parameters around reasonable supervision when a person has to provide a urine sample.

Blood samples are another body sample used for forensic toxicology. A huge range of toxic substances can be tested from a blood sample. You may already be familiar with blood alcohol testing used to assess if a person was driving under the influence of alcohol. This type of testing is important in assessing if a driver is above the legal limit and it is also used to prove a case in court.

Hair samples are a good way to test for substance abuse that has occurred over the long-term. After a person ingests a chemical, it ends up in the hair, where it can provide forensic toxicologists with an estimate of the intensity and duration of drug use. Hair testing is even offered quite widely by companies that allow you to mail in a hair sample and check off the drugs you want checked. Saliva is another way that forensic toxicologists can test for drugs. It does, however, depend on the drug in terms of identifying its concentration. One of the more unusual sounding but interesting ways that the human body can be used for forensic toxicology involves the gastric contents in a deceased person. During the autopsy, a sample of the person’s gastric contents can be analysed, which then allows the forensic toxicologist to assess if the person took any pills or liquids before their death. The brain, liver and spleen can even be used during toxicology testing.

Forensic Toxicology Applications

While there are many uses for forensic toxicology testing, the most familiar one to most people is likely to be drug and alcohol testing. This type of testing is commonly performed in the transportation industry and in workplaces. Another use is for drug overdoses, whether these are intended or accidental. People who drive with a blood alcohol concentration over the accepted legal limit can also be assessed through toxicology testing. Another application of forensic toxicology relates to sexual assault that involves the use of drugs. Various drugs are used today for the purposes of rendering the victim unable to fight the attacker, who then proceeds to sexually assault the victim. Through toxicology testing, a victim can find out what drug was given and can then be treated accordingly.

There are a lot of substances and poisons in our world – many of which impact how we function in work and society. For some people, these substances can influence their death. Fortunately, forensic toxicology testing allows forensic scientists to identify substances and determine a pattern of use. In this way, a forensic toxicologist can provide closure on the ‘what if’ of a person’s drug habits or perhaps some mystery surrounding their death.

This article first appeared on Explore Forensics on the 4th of September 2014 and was authored by Ian Murnaghan – BSc (hons), MSc.