Forensic

Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting
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Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting

The use of fingerprints as a means of identification has been successfully implemented worldwide. But how did the idea of using these unique impressions in a forensic setting first come about? Many scientists are known to have been involved in the early research relating to fingerprinting, dating right back to the 1600s, but Sir Francis Galton and William Herschel are widely recognised as the real pioneers of forensic fingerprinting.

However the story actually begins with the work of another man: Henry Faulds. In the late 1880s, the Scottish physician was working in Japan in a number of roles, one of which caused him to be involved in various archaeological digs. During this time he first stumbled upon the uniqueness of fingerprints after discovering prints left behind by craftsmen in old pieces of ceramic pottery. This allegedly inspired his notion of using fingerprints to identify criminals, at which point he promptly published an article in Nature detailing his thoughts on the matter. In his manuscript, “On the Skin-Furrows of the Hand”, Faulds suggested the possibility of using fingerprints to identify individuals, however did not provide anything to support his theory other than the anecdotal evidence of his own use of fingerprints to identify the perpetrator of a break-in at his hospital. Back in the UK, Faulds shared his ideas with Scotland Yard, but they unsurprisingly had no interest in this somewhat unsupported theory. Incidentally, Faulds also shared his work with Charles Darwin. Although Darwin did not pursue the research himself, he did forward the information to his cousin, Francis Galton. At the time, nothing came of this interaction.

Shortly after Fauld’s publication in Nature, William Herschel, a British civil servant who was based in India at the time, soon published a responding letter in Nature claiming he had been using fingerprints as a means of identification for years. A very public argument over who should claim credit for this idea ensued between the two scientists which lasted for years, though the world paid little attention. There was quite simply no data to support the claims of the two men.

A couple of years later, Sir Francis Galton once again enters the picture. Now heavily involved in the field of anthropometry (the study of measurements of the human body), he began working with Herschel to gather the much-needed data necessary to support the theory of fingerprints as a means of identification. Galton’s research allowed him to collect thousands of fingerprints and ultimately conclude that fingerprints were in fact unique to the individual, could persist on a surface for years if not decades, and could be easily used to develop a system of storing and comparing prints. Galton presented his findings at the Royal Institution, sharing his and Herschel’s research in fingerprinting as a means of identification. Based on Galton’s work, the use of fingerprinting was finally considered by Parliament in 1894, and was soon implemented in criminal investigations. Galton and Herschel were now viewed as the original pioneers of forensic fingerprinting, whereas Faulds later spent years fighting to be recognised as the true founder, petitioning to academic journals, newspapers and even the Prime Minister.

In 1892, anthropologist Juan Vucetich made history by using fingerprint evidence to positively identify the culprit in a criminal case. When the children of Francisca Rojas were found murdered, Vucetich implicated Rojas when a bloody print allegedly proved she was the murderer. Since then, the study and use of fingerprints has been a fundamental aspect of forensic investigations worldwide.

References

Faulds, H. On the Skin-Furrows of the Hand. Nature, 1880, 22.

Stigler, S. M. Galton and Identification by Fingerprints. Genetics. 1995, 140(3), 857-860.

University of Glasgow. Henry Faulds. [online] Available: http://www.universitystory.gla.ac.uk/biography/?id=WH25214&type=P

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Interview with Program Director Max Houck

What is your current job role and what does this position involve?

My current role is Visiting Assistant Professor and Director of the Forensic Studies & Justice Program at University of South Florida St. Petersburg. The Program teaches forensic investigative techniques and scientific applications in criminal cases, using structured analytic techniques borrowed from the intelligence community to mitigate and reduce bias, and how to improve the criminal justice system and avoid wrongful convictions. I created the Program, teach in it, and conduct research in these areas.

How did you come to work in the field of forensic science?

I became interested in forensic science through taking anthropology courses for my undergraduate minor; I was originally in International Relations and was going to be a translator (Russian and Japanese). Ultimately, bones made more sense than conjugating irregular Russian verbs and I changed majors. In my Masters work, I was a student of Jay Siegel, who set me on my path to a forensic science career.

What would you say has been the highlight of your career to date?

Being Director of the Washington, D.C. Department of Forensic Sciences. I structured the new agency, created many of its new policies for independent science, and worked with people who remain my heroes for what they do.

During your years working in forensic science, how do you feel the field has changed?

I worry that the field has become a bit of a cargo-cult science–we’ve “drunk our own Kool-aid”, as the saying goes. We believe if we SAY something is “scientific”, then it IS scientific. We’ve also come up with some fairly suspect ways of justifying bad or marginal science and these have been accepted by an all-too-willing court system. That is beginning to change, a little, with some good basic research into the fundamentals of our science but we’re still hampered by trying to be the servant of justice instead of a partner in the process.

In recent years, concerns over the reliability of some forensic techniques have been raised in the media. What steps do you think we need to be taking to ensure that only scientifically reliable techniques are utilised in legal investigations?

First and foremost, forensic agencies need to be independent of law enforcement; that won’t solve everything but it’s a good start to ensure we’re not marginalized. Second, we need to stop worrying about new methods and shore up the ones we’re already using–do they work and, if so, how well? Finally, we have to be better communicators about what we can and cannot say and why. Being pressured by money, time, or politics only gets you shoddy results–just look at any of the latest “forensic failures”.

Finally, do you have any words of wisdom for those pursuing a career in forensic science?

Be a scientist first; the application to criminal cases can come later. Don’t job hop; keep your first job at least two years and then move up or out. And last, don’t worry about ethics, worry about integrity. Ethics is knowing right from wrong and prisons are full of people who know the difference, they just lacked the integrity to make the right choice.

 

Sweat Security: Using Skin Secretions for Authentication
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Sweat Security: Using Skin Secretions for Authentication

The use of passwords and pin numbers is part of our daily lives, being a necessity in ensuring our data and money doesn’t fall into the wrong hands. However passwords and pattern-based pins have their obvious limitations, and they are only as secure as the user is cautious.  One method of improving security utilises biometric technology, which is based on the biological or behavioural characteristics of an individual. Biometric-based security systems are certainly nothing new. The concept of using fingerprints, retinal scans and voice recognition as security measures materialised decades ago, and such techniques are frequently used for authentication purposes. Despite these technological developments, ongoing research is attempting to develop more robust and secure methods of identification.

Researchers at the University of Albany are developing a unique new technique of biometric identification using only a person’s sweat. Human sweat, and all body fluids for that matter, contains a plethora of chemical compounds, ranging from small weight molecules to large proteins. These compounds originate from a variety of sources, with some resulting from endogenous metabolic processes within the body, and others being introduced through diet and environmental exposure. Metabolite levels can be affected by an endless array of factors, including sex, ethnicity, age and lifestyle. Interestingly, it is now known that the presence and amount of some of these compounds can vary greatly between different people, thus in theory unique metabolome profiles could be harnessed for identification purposes.

phone

The compounds the technique will focus on is vital, as certain chemical levels can fluctuate wildly throughout the day depending on what we have eaten, for instance. However levels of certain chemicals have been found to be relatively stable or at least only vary gradually. In this research, Assistant Professor Jan Halámek and his team focused on using amino acid profiles of sweat to offer a unique means of authentication.

By first establishing which amino acids are present in a person’s skin secretions, a wearable device can then be constructed which will monitor the levels of these compounds. The device would initially require a kind of enrolment period, during which time the user’s skin secretions would be constantly measured in order to develop a unique profile of metabolites. It is already known that the metabolites released by the body vary throughout the day, so such a monitoring period would be necessary to take into account these changes.

Over time a profile of the user’s skin secretions would be built up and stored within the device, acting as a kind of standard for comparison. When future skin secretions are analysed by the device, the profiles will be compared with the known user profile and used to confirm the identity of the user. In the event of anyone else picking up the device, the instrument would detect a different skin secretion profile and lock the device or turn it off, thus ensuring security of the smartphone or computer.

If successful, the technology could offer an improved active authentication system, either as a standalone system or supplementing existing technology. However the technique is very much in its infancy and a great deal more research will be required before this kind of technology is rolled out commercially, if it ever is possible. It is likely that such a technique will be affected by contamination, for instance as the user’s hands become dirty throughout the day or if cleaning or cosmetic products are applied to the skin. Furthermore, if authentication is based on comparison with an electronically stored profile, the device may still be susceptible to hacking in order to bypass the security system. But if this technique could reach a sufficient level of robustness, the days of struggling to remember your password could be eliminated.

 

Agudelo, J. Privman, V. Halamek, J. Promises and Challenges in Continuous Tracking Utilizing Amino Acids in Skin Secretions for Active Multi-Factor Biometric Authentication for Cybersecurity. ChemPhysChem. 18, 1714-1720 (2017).

Tracking Illicit Drugs with Strontium Isotope Analysis
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Tracking Illicit Drugs with Strontium Isotope Analysis

The manufacture and distribution of illicit drugs such as heroin is a primary focus of many major law enforcement organisations worldwide, including the Drug Enforcement Agency (DEA) in the United States and the National Crime Agency (NCA) in the United Kingdom. Unfortunately, as drug shipments pass hands between dealers and cross borders so rapidly, it can be difficult if not impossible to trace a batch of drugs back to an initial manufacturer. As a result of this, the chances of locating and arresting the manufacturers of illicit drugs can be slim.

To a forensic drugs analyst, a whole range of characteristics can be examined and used to classify and compare different batches of the same drug, including physical appearance, packaging, and chemical composition. To an extent, heroin chemical signatures are already beneficial in comparing different batches of the drug in attempts to establish links and possible sources of the narcotics. This may be based on agents or adulterants a product has been cut with, and the relative concentrations of those substances. The manufacturing process itself can vary in terms of chemicals and apparatus used and the skills of the manufacturer, resulting in further characteristic differences in the chemical profile. However these differences may not be distinct enough to be valuable and are certainly not able to pinpoint the country from which a batch originated. Though there is still no reliable method of tracing an illicit drug back to a particular location, ongoing research is aiming to change this.

One method of studying the history and even origin of a sample is to use isotopic composition. Isotopes are different forms of elements that are incorporated into substances in the environment in varying ratios and abundances, influenced by a number of factors that can alter these ratios. These processes can be described as isotopic fractionation. Interestingly, isotopic ratios can be characteristic to different regions of the world, enabling certain materials to be traced back to the geographic region based on the ratios of particular isotopes contained within that material. With this in mind, they have often been used to trace unidentified human remains to a particular location or study the origin of food products. Focusing on isotopes allows for heroin samples to be studied and compared based on regional characteristics as oppose to the variation caused by the production process.

For the first time, researchers at Florida International University have utilised strontium isotope ratio analysis to determine the provenance of illicit heroin samples. 186 unadulterated, undiluted heroin samples of known origin were obtained from a number of geographic regions including Southeast Asia, Southwest Asia, South America, and Mexico. Of a particularly challenging nature is South American heroin and SA-like Mexican heroin, which can be extremely difficult to differentiate based on their chemical compositions alone. Heroin samples were dissolved via a microwave-assisted acid digestion method before being subjected to a technique known as a multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS). This instrument utilises an inductively coupled plasma ion source to ionise target analytes, which are then separated and analysed by the mass spectrometer. The use of MC-ICP-MS allows for the strontium concentration of particular samples to be determined. The strontium isotope ratio (87Sr/86Sr) value of each individual sample was then compared with the overall mean values of ratios from different regions in order to establish the likely origin of that particular heroin sample. Samples from the same geographic region would be expected to exhibit a similar isotope ratio.

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Multi-collector inductively-coupled plasma mass spectrometer (MC-ICP-MS) Source: www.thermofisher.com

The results demonstrated the possibility of differentiating between heroin of different geographic origin. South American and Mexican heroin samples were correctly classified 82% and 77% of the time respectively. South East and South West Asian heroin samples were somewhat more difficult to differentiate due to more of an overlap between strontium isotope ratio values. SE Asian samples were correctly classified 63% of the time and SW Asian samples only 56% of the time. It is not clear whether this elemental strontium is endogenous or the result of external contamination, but either way it is sufficiently characteristic to be associated with a particular geographic location.

The strontium isotope composition of heroin can be affected by a number of factors, including the soil in which components are grown and groundwater in the area, which can result in region-specific isotope compositions. The use of strontium isotope ratio analysis has presented promising results in the origin determination of illicit heroin. Although a larger scale study incorporating samples of a more worldwide origin would be ideal, initial results suggest that this technique could allow for an unknown illicit drug sample to be traced back to a country of origin, aiding criminal intelligence agencies in the war against drugs.

 

Debord, J., Pourmand, A., Jantzi, S., Panicker, S. & Almirall, J. Profiling of Heroin and Assignment of Provenance by 87Sr/86Sr Isotope Ratio Analysis. Inorg Chim Acta. In press (2017).

Instant Insect Identification to Aid Forensic Entomology Investigations
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Instant Insect Identification to Aid Forensic Entomology Investigations

During the investigation of a suspicious death, entomological (that is, insect-related) evidence may be able to provide vital clues as to when the victim died. Determining time since death, or post-mortem interval, can be one of the most important aspects of such an investigation, so it comes as no surprise that a great deal of research has been directed towards improving these estimations.

Insects can play a huge role in estimating time since death. Various types of species of insect will often visit the scene of a death in a relatively predictive manner, either to feed on the decomposing remains (known as necrophagous insects), to prey on other insects present, or to find a suitable place to lay their eggs. Blow flies, a group which includes common flies such as the bluebottle and the greenbottle, are often of particular interest. Forensic entomologists will typically study the insects, eggs and larvae present at a death scene, utilising the type of bugs found and their stage of development to track back to the likely time at which they arrived, thus when the victim may have died. However in order to accurately do this, entomologists must often collect insect specimens for closer inspection and even to rear to adulthood in order to determine the exact species, which is evidently a time-consuming process requiring a high level of expert knowledge.

For the first time, researchers at the University of Albany have applied a technique called direct analysis in real time with high resolution mass spectrometry, or DART-HRMS for short, to the analysis of blow fly eggs. Published in the latest issue of the journal Analytical Chemistry, the technique has demonstrated the possibility of almost instantly differentiating between different fly species based on the amino acid profiles of the eggs.

DART-MS, developed in 2005 by Dr Chip Cody of JEOL, is an ambient ionisation mass spectrometry technique that allows for samples to be directly analysed without any time-consuming sample preparation steps, and perhaps most importantly without destroying the sample. The sample is simply presented in its native state between the ion source and the inlet of the mass spectrometer, enabling compounds present in the sample to be ionised and drawn into the instrument for analysis and identification.

dartms

Sampling interface of DART-MS. Source: Wikimedia Commons

During this investigation, researchers used pieces of pork liver to attract a number of different blow fly species before transporting them to the laboratory. The flies were reared until they lay new eggs, which would be the focus of the analysis. The study utilised specimens of a number of species, including Calliphora vicinia, Lucilia coeruleiviridis, Lucilia sericata, Phormia regina, along with specimens from the Phoridae and Sarcophagidae families. Even to the eye of an expert, the eggs of these specimens are often indistinguishable. The eggs were simply placed in an ethanol solution and the mixtures directly subjected to DART-HRMS analysis.

The technique focused on the analysis and identification of amino acids in the eggs, essentially enabling researchers to produce a chemical fingerprint unique to eggs of a particular species. Examination of the mass spectra showed that the different species exhibited a unique chemical fingerprint, and by using multivariate analysis it was possible to better visualise the similarities and differences between amino acids detected in the eggs of different species.

Unsurprisingly, many amino acids were common to multiple species. For instance, alanine, isoleucine and proline were detected in four of the species, whereas valine was detected in all but one of the egg samples. However some compounds were unique to particular species, and it is these unique amino acids that will prove to be most beneficial in differentiating between the eggs of different species. For instance, glutamine and tryptophan were only present in the eggs belonging to P. regina. Interestingly, the research also demonstrated the ability to distinguish between families as well as species, with some compounds only detected in the eggs of specific families.

By using this particular technique, almost instantaneous identification could be achieved. Of course this research has included only a very limited number of species, thus a much bigger investigation would be necessary before the technique would really be beneficial to a legal investigation. Not only would further species need to be included, but another potential development would be the production of a chemical profile database against which unknown insect samples could be compared. Developed further, the use of DART-MS could save investigators a lot of time in the identification of insects of forensic interest.

 

References

Cody, R. B., Laramée, J. A. & Durst, H. D. Versatile New Ion Source for the Analysis of Materials in Open Air under Ambient Conditions. Anal. Chem. 77, 2297–2302 (2005).

Giffen, J. E., Rosati, J. Y., Longo, C. M. & Musah, R. A. Species Identification of Necrophagous Insect Eggs Based on Amino Acid Profile Differences Revealed by Direct Analysis in Real Time-High Resolution Mass Spectrometry. Anal. Chem. (2017) In Press

 

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Interview with Forensic Physician Samar Abdel azim Ahmed

samar

What is your professional background in forensic science?

I am an associate professor of Forensic Medicine in Ainshams University Faculty of Medicine in Egypt. I received my doctorate degree 10 years ago with honours from ASU and then proceeded to work on my educational capacity. I studied for a second Masters degree from Maastricht University and Suez Canal University in Health professions education. I then received a scholarship from ECFMG in USA for a fellowship program in Health professions education in FAIMER, Philadelphia.

What is your current job role and what does this work involve?

Currently I teach forensic Medicine to fourth year medical students together with my administrative job as the director of the Centre of Excellence in Forensic Psychiatric research. This centre is a product of a Newton Mosharafa Fund that I received from the British council and the Science Technology Development fund in Egypt to establish forensic psychiatry research trends in Egypt. At the moment I am working on establishing partnerships within the scope of forensic psychiatric service improvement.

What initially attracted you to this field of work?

I am a physician by training but I was attracted to the field of forensics mainly challenged by the importance of the service that one can offer to justice by giving a voice to the voiceless. My work as a forensic physician is mainly to advocate for those who are victimized and to prevent further injustice by uncovering the truth that can only be seen by forensics.

Can you tell us about the research you are currently involved in?

At the moment my point of focus is forensic psychiatric patients. I am indulged in studying the service offered in my country with the hope that I can import state of the art practices from the UK utilizing the cooperation agreement that I have set with them. The first part of the study is mapping the patient’s body in Egypt with special reference to the determinants of the length of their stay in the high secure wards. This requires a lot of work to establish a culture and understanding of predictors of violent behaviour. This work comes within my funded project that we have now come to call LIFE project.

Why is this work important to the field of forensic science and what do you hope to achieve by carrying out this research?

Our hope is to be able to establish guidelines to predict violent patient behaviours and thus be able to predict patients who are in need of extended stay in forensic wards. This will help in turn to reduce unnecessary length of stay of patients. By the end of this work I hope to be able to publish a white paper of effective forensic psychiatric practice as a guiding document to help in the decision making process when patients are discharged.

Do you have any words of advice for students wishing to pursue a career in your field of work?

My advice for students who want to pursue a career in forensic medicine is to specialize as early as possible. The earlier you specialize and maybe even subspecialize the quicker you grow in the field. Master your passion area and own it then try to build on it from early on. You build your name from day one in the field so build a name that goes with a specialization. It is also important to understand why you are in the field. Understand that you give bones a voice and that without you the truth will be buried indefinitely so it is important to take this calling very seriously.

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Keeping the Skies Safe with Analytical Chemistry

Ever since events such as 9/11, the Lockerbie bombing and the (fortunately) failed shoe bomber, the stringency of airport security has been ever increasing. Anyone who has passed through an airport has no doubt witnessed the occasional swabbing of luggage or electronic items. The staff will take a quick swab of the item, stick it into a mysterious machine and usually send the passenger on their way with little explanation of what has just occurred.

But what exactly are they testing for in this scenario, and just what is the instrument they’re using?

As one might expect, the biggest target of this security step is explosive substances as a counter-terrorism measure, in addition to illicit narcotics in an attempt to crack down on drug trafficking. In an airport setting, the analytical testing technique of choice is ion mobility spectrometry.

Ion mobility spectrometry (IMS) is an analytical technique used to identify chemical compounds based on the differences in the movement of ions under an electric field. The concept for the technique was established in the early twentieth century, however it was not until the 1970s that the instrumentation was actually properly developed. There are currently tens of thousands of IMS devices deployed around the world. Not only are they utilised in airports for drug and explosives screening, but also by the military for the detection of chemical warfare agents and in industrial settings to monitor air quality. The range of applications is potentially vast, but the principles of operation are the same.

As you may have witnessed, a small swab is rubbed over the surface to be tested, typically a piece of luggage or an electronic device such as a laptop, before being inserted into the ion mobility spectrometer. As the sample needs to be introduced in its gaseous form, the swab may be subjected to heating in order to thermally desorb analytes from the swab and allow them to be transported into the instrument for analysis. In order to manipulate the analytes entering the instrument, they must first be converted into ions, their charged form. Ionisation is typically achieved using a radioactive source, such as 63Ni (nickel-63) or 241Am (Americium-241), which first form reactant ion species from the carrier gas (usually air), which then leads to the ionisation of the sample material. These newly-formed ions will then enter a region under an electric field and drift towards a series of electrodes. The ions will pass through the drift region at different speeds depending on the shape and size of the ion clusters and strike the electrodes, the signals being amplified and detected. Depending on the instrument and needs of the analysis, either positive or negative ions will be produced (in some cases both simultaneously).

ims

IMS schematic. Source: Smiths Detection (www.smithsdetection.com)

The IMS utilised in airports will typically hold a database of known explosive and narcotic substances against which to compare samples. There will be a certain threshold, typically based on peak intensity, that must be reached before a positive identification will be indicated, and if there is a “match”, the operator will be alerted to a potential identification.

In comparison to other analytical tools available, ion mobility spectrometers are far from being the best. For instance mass spectrometry, an alternative technique for the analysis and identification of chemical compounds, can offer greater sensitivity, higher resolution, improved accuracy and better identification. So why use IMS? It essentially comes down to cost and ease of use. The simple design and ability to operate at atmospheric pressure means the instruments can be fairly small in size, some even being hand-held and so rendering them completely portable. They have low power consumption, so can simply be powered by a few AA batteries. The ease of use of the IMS means anyone can be trained to use the instrument, thus technical or scientific expertise is not required.

But what is perhaps most important for use in an airport setting with potentially thousands of passengers each hour, is the ability to conduct analyses quickly, and this is something that the IMS can offer. Many commercial ion mobility-based instruments can provide results in a matter of seconds. For instance, the IONSCAN by Barringer (now owned by Smiths Detection) boasts the ability to detect over 40 explosives and narcotics in just 8 seconds.

In a security setting there are three primary types of IMS that may be encountered. The smallest of the devices are handheld and sample by drawing in analytes present in the atmosphere. These may be used to analyse potential hazards relating to unattended baggage, for example. The second type, which is perhaps the most commonly encountered IMS in airports, is a benchtop instrument which requires introduction of the sample via some type of swab. And finally, some airport security units may utilise a larger, human-sized IMS portal. This setup uses airflow to dislodge particles of explosives or drugs from clothing or the passenger’s body and analyse them.

Unsurprisingly, the instruments are not infallible, and false positive or negative results are a possibility. Some ions will have the same drift time so may be indistinguishable from known explosives or drugs, triggering an alarm. In actual fact this response may simply have been caused by a cosmetic or pharmaceutical product that happens to produce a response similar to a known narcotic. On the contrary, dirt, oil and other contaminants may mask the presence of substances of interest, thus causing no alert despite the presence of a drug or explosive.

Furthermore, the IMS is somewhat limited in that it can only identify the presence of a compound contained within its database. So whereas it may be able to detect common explosives such as RDX, TNT and PETN, and frequently encountered narcotics such as cocaine, heroin and cannabis, it would not necessarily alert to the presence of an unknown compound (unless it was very similar in chemical structure to something in the database).

Fortunately research in the field of analytical chemistry is constantly ongoing, aiming to improve instrumentation and analytical techniques to resolve these issues and ultimately produce more reliable and robust security measures.

 

References

G. Ewing et al. A critical review of ion mobility spectrometry for the detection of explosive and explosive related compounds. Talanta. 54 (2001) 515-529.

Homeland Security Science & Technology. IMS-Based Trace Explosives Detectors for First Responders. [online] Available: https://www.dhs.gov/sites/default/files/publications/IMSTraceExploDetect-SUM_0506-508.pdf

Smiths Detection. Ion Mobility Spectrometry (IMS). [online] Available: https://www.smithsdetection.com/index.php?option=com_k2&view=item&layout=item&id=40&Itemid=638

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VX and Other Deadly Nerve Agents

It has now been confirmed that Kim Jong-nam, the half-brother of North Korean Leader Kim Jong-un, may have been assassinated using a highly toxic nerve agent known as VX. The attack occurred last week (13th February) in Kuala Lumpur airport, suspected to have been committed by two women who reportedly sprayed the chemical into his face before fleeing the scene.

VX, or S-[2-(Diisopropylamino)ethyl] methylphosphonothioate, is a nerve agent initially developed at the Porton Down Chemical Weapons Research Centre in Wiltshire, UK in 1952. Having originally been the focus of research elsewhere into the development of new organophosphate compounds as pesticides, the British military soon established an interest in the compound and continued its development.

vx-wiki

S-[2-(diisopropylamino)ethyl] methylphosphonothioate) or VX

Typically encountered in liquid form, this clear or sometimes amber-coloured, oily substance is notoriously difficult to detect, lacking in both taste and odour. Its toxicity makes it one of the deadliest chemical warfare agents, requiring as little as 10mg adsorbed through the skin to be fatal. Its deadliness is only further increased by the persistence of the agent, making it difficult to decontaminate people and areas tainted with the chemical.

Mechanism

The mechanism of action of VX is identical to many similar nerve agents. The compound can enter the body by a range of potential routes, including ingestion, inhalation or skin contact. Once inside the body, VX inhibits the function of acetylcholinesterase (AChE), an enzyme responsible for catalysing the breakdown of acetylcholine. Acetylcholine is released over a synapse following an electric nerve impulse, ultimately resulting in a muscle contraction. However when VX binds to the active site of acetylcholinesterase, it renders the enzyme inactive, thus preventing it from breaking down the acetylcholine. As the nervous system is flooded with excess acetylcholine,  repeated muscle contractions occur, eventually resulting in asphyxiation due to constant contraction of the diaphragm muscle.

The effects of VX will typically occur immediately after exposure, beginning with coughing, shortness of breath and a tightness in the chest. A headache and blurred vision soon follows, along with symptoms such as vomiting, diarrhoea and abdominal pains. Given a sufficient dose, seizures will then occur as the drug attacks the nervous system, eventually resulting in a coma and asphyxiation.

If administered promptly, there are antidotes for VX. Atropine, typically administered by injection, is an anti-nerve agent that blocks the acetylcholine receptors, alleviating the symptoms brought on by the nerve agent. However it is worth noting that compounds such as atropine are toxic in their own right and, although they may save the person’s life by alleviating the effects of the nerve agent, they will still have an adverse effect on the patient. In addition to this, pralidoxime (or 2-PAM), can be administered to reactivate the enzyme, thus reversing the effects of VX. 2-PAM is a safer compound to use than atropine, but its effects are much slower.

Other Nerve Agents

VX is just one of many known toxic nerve agents. Nerve agents can typically be classed as either G-series or V-series. G-series agents were first synthesised by German scientists during World War II, and include tabun (GA), sarin (GB), soman (GD), and cyclosarin (GF). The first compound to be discovered, tabun, was accidentally synthesised by Dr Gebhardt Schraeder, who was investigating the development of organophosphate-based pesticides. The German army soon realised the potential use of such compounds, and went on to fund the development of other nerve agents such as sarin. The G-series chemicals are all clear, colourless liquids at room temperature, but are largely utilised as gases due to their high volatility.

The V-series nerve agents, which include VX, VE, VG, VM and VR, were developed a few years later, initially in the UK but some later in Russia. Unlike the G-series compounds, V-agents are very persistent and are not easily washed away or degraded, meaning they can remain on surfaces for long periods of time.

Fortunately the V-series nerve agents have generally not been exploited outside of military research, and the death of Kim Jong-nam may well be the first known use of the toxic agent in an assassination. However the G-series have received a great deal of malicious use and attention over the years, ranging from the Tokyo sarin subway attack in 1995 to its recent use in the Syrian civil war

VX, along with numerous other toxic nerve agents, were banned under the Chemical Weapons Convention of 1993, rendering the manufacture, possession and use of such substances illegal.

 

References

BBC News. VX nerve agent: The chemical that may have killed Kim Jong-nam. [online] Available: http://www.bbc.co.uk/news/world-asia-39073558

University of Bristol Chemistry on the Screen. VX Nerve Gas. [online] Available: http://www.chm.bris.ac.uk/webprojects2006/Macgee/Web%20Project/nerve_gas.htm

 

 

 

 

 

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Interview with Forensic Archaeologist & Researcher Amy Rattenbury

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What is your current job role and what does this involve?

By training I’m a Forensic Archaeologist but currently work as a lecturer at Wrexham Glyndwr University teaching on the BSc (Hons) in Forensic Science. My day to day job is teaching student groups across all three years of the programme in a range of subjects such as Crime Scene Investigation, Anatomy & Pathology and the Forensic Investigation of Mass Fatalities. As well as delivering the theory I set up a lot of the practical work that the students do such as fingerprinting workshops, organ dissections and simulated crime scenes that we mock up in our Crime Scene House. I also supervise a number of student research projects mainly in the area of Taphonomy which we conduct on our ‘Body Farm’

What initially attracted you to this field of work?

I had always been interested in science and particularly forensic science and initially took a degree in Forensic Biology at Staffordshire. I always imagined that I would go on to work in a laboratory or doing fingerprint comparisons until I took a module in ‘Identification of Human Remains’. This really sparked my interest in human osteology and made me pursue a MSc in Forensic Archaeology and Crime Scene Investigation at Bradford University where I found my very niche area in search and recovery of human remains. I started teaching anatomy alongside completing my MSc and found a real love for being in the classroom. It gives me an ideal role in being able to share what I’ve learnt so far whilst still being able to pursue my own research and industry related work. Looking back now I can’t imagine not being a teacher. There’s something about introducing students to concepts they had never considered before that really exciting. And sometimes they come back to you later on in their academic careers and actually end up teaching you something; that’s a really rewarding feeling.

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Can you tell us about the research you are currently involved in at Wrexham Glyndwr University?

We are really lucky here at Glyndwr to have Wales’ first and only Taphonomic Research Facility which is licensed by DEFRA. This ‘Body Farm’ allows us to conduct a number of research projects looking at decomposition which could necessarily be hosted by other universities without a dedicated, rural area in which to conduct their research. This coupled with a high calibre research lab in our Chemistry Department has really allowed both myself and students to expand research ideas. Current student projects which are out on the body farm include:

  • The effect of clandestine burial decomposition on soil chemistry and vegetation
  • How tattoo identification is effect by post mortem changes
  • A comparison of decomposition rates in fresh and stagnant water

I am also hoping to set up my own research once the temperature improves slightly and this will be looking at how oxygen deprivation (i.e. vacuum packing) affects taphonomic changes. This is a research project based on a pilot study I supervised, conducted last year by Shareei Singer at the University Centre Southend, and we hope to expand this further by looking at more samples, over a longer time frame whilst also improving the analysis methods used.

What are some of the biggest challenges in your field of work?

Teaching is a challenging role in the first place, but even more so at University level where there is an increased need to challenge students academically, and this can be particularly difficult field to get in to early in a professional career. I’m only 25 so it’s been very much a case of putting myself out there for any and every opportunity to prove myself and gain any experience I can. You really have to show not just your ability as an academic but also a drive and passion for the subject and the students. It is a highly competitive area, not only in terms of securing jobs in the first place, but then going on to conduct and publish research whilst still maintaining high quality, engaging session, for students every week. For me in particular, I find the sheer volume of books and journals I have to read, to ensure that my delivery keeps up with the speed that the area is progressing, a little daunting. But when it’s a subject that I’m passionate about, and books I would likely read anyway, it does make it easier!

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Aside from research, are you often involved in police casework or consultancy work, and what does this typically involve?

I’m not currently involved in any active police work but I did only move up to North Wales around 6 months ago. It is something that I am very keen to start and hope to build up connections in the area to so this. I do some other consultancy work in different areas of forensic search. I work quite closely with UK-K9 who are a search dog training team. They specialise in training dogs to search for a variety of forensic evidence including human remains, explosives and drugs. We are currently working to improve the use of the human remains detection dogs on water and particularly in salt water setting such as costal searches. They are also involved in a lot of cold case reviews and large scale searches which I can offer an archaeological perspective on. I have also recently taken up a consultancy position with Kenyon International Emergency Services who deal with crisis incidents world-wide. I am currently awaiting deployment but once I am called in the role could be anything from collecting evidence at aeroplane crash sites to helping with disaster victim identification during natural disaster.

Do you have any words of advice for students wishing to pursue a career in your field of work?

For students wanting to go in to the forensic science generally just make sure you have it clear in your head before you start that it isn’t going to be how you see things portrayed in the media, I wouldn’t want you to be disappointed or put off once you start the course. I would say trying to get any sort of work experience is going to be crucial. Experience is essential nowadays but still almost impossible to get in crime related areas so think outside of the box a little bit. There are lots of labs you could do placements in that, although aren’t forensic can help you to learn and demonstrate key skills. I worked in a drinking water testing lab and in a haematology lab for a little while, both of which helped learn more about preventing cross contamination. But there are lots of other areas you can volunteer in such as becoming a PCSO, the Appropriate Adult services or any other charity that deals with victims of crime or offenders.

For students wanting to become educators I would say persevere. Remember what made you so passionate about that subject in the first place and share this with you students. It’s amazing how much more progress you make once you’ve learnt to foster this positive learning and collaborative environment. The planning and the marking will get easier, I promise!

 

Follow Amy on Twitter at @amy_rattenbury

Forensics at Glyndŵr can be followed on Twitter or Facebook.

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Interview with President of IsoForensics Inc., Lesley Chesson

southern-utahDifferent forms of elements–called isotopes–are found everywhere in the environment. These isotopes are incorporated into materials in varying ratios and the abundances of different isotopes thus serve as a record of the material’s formation. Analysis of a material for its distinct isotope signature can subsequently be used to reveal its history. Investigators have applied stable isotope analysis to a variety of materials of forensic interest including drugs, explosives, money, food, ivory, and human remains. For example, the isotopes in human hair protein can reveal the age of an individual, what s/he ate, and even how often (and where) s/he travelled.

What is your professional background and how did you come to be involved in IsoForensics?

I have a master’s degree in biology, with a lot of microbiology and chemistry experience. I entered the world of isotope forensics when I was hired to raise Bacillus subtilis (a cousin of the anthrax bacterium) under a variety of conditions – in liquid media, on agar plates, with different nutrients, etc. Because organisms record information about the environment in the isotopes of their tissues, the goal of this project was to develop models that allowed investigators to predict the growth conditions of a dangerous bacterium–such as anthrax–from its isotopic characteristics.

From its start in academia, IsoForensics developed into a private analytical services and research firm that explored novel forensic applications of isotope analysis. I enjoyed the challenges offered by that exploration. Since my first work on the B. subtilis project, I’ve been involved in other projects on human remains, foods and beverages, illicit drugs, and explosives.

Tell us about the work IsoForensics is involved in and what kind of clients do you typically work with?

Currently, IsoForensics provides a lot of human remains testing in unidentified decedent cases. The goal is to use the isotope records contained in hair, nails, bone, and teeth to reconstruct the travel history of individuals and provide new evidence on their origins: Were they local to the area of discovery? Had they traveled prior to death? Where might they have traveled? We work with a variety of law enforcement groups in this casework.

In addition to service work, we conduct basic and applied research through funded grants and contracts. One recent project has started to investigate the origins and ages of seized elephant ivory to understand the structure of illegal trade networks in Africa and Asia.

What are some of the most common sample types you are asked to analyse, and does anything pose a particular challenge?

In any given month, we can analyze a variety of materials – human and wildlife remains, illicit drugs, explosives, etc. One of the most challenging measurements we make is for strontium isotope ratios. There is so little strontium contained in organic materials that prep work takes place in clean lab settings. The preparation of materials for radiocarbon dating is also challenging since we must be extremely careful about contamination of “old” materials with “modern” carbon. However, these challenges are worthwhile since strontium isotopes can provide potentially useful geolocation data about materials while radiocarbon dating provides quantitative information on the “age” of materials.

Are there any areas of isotopic analysis that could benefit from further research and development?

Yes. Isotope forensics benefits from better and better models/methods for interpreting data. It’s one thing to compare isotope measurement results from sample to sample or from sample to a reference databank, but it’s another thing altogether to understand the process(es) driving isotopic variation in materials. For example, are the results we observe due to differences in TNT manufacturing process? Or coca plant physiology? Or elephant diet?

Isotope analytical techniques also change over time as better instrumentation is developed. Understanding the impact of different analysis techniques on measured isotope ratios is extremely important when comparisons are made – especially in legal settings. A major focus of the field is the standardization of practices and protocols, to generate comparable results over time and space (e.g., from lab to lab).

How has the need for isotope analysis in forensic investigations changed over the years, if at all?

The forensic application of isotope analysis has been increasing the past 10-20 years. This is partly due to changes in analytical techniques, which have made isotope ratio measurements faster and cheaper. In addition, those who could benefit most from forensic isotope data–law enforcement, regulators, etc.–have become more aware of the technique and it potential usefulness in various types of investigations. We as forensic scientists and isotope analysts can do even more to spread awareness about the technique and its many applications.

Finally, do you have any advice for students hoping to pursue a career in this field of work?

Isotope analysis is one (extremely useful!) tool in a forensic scientist’s toolbox. Having a background and training in other areas–such as anthropology, analytical chemistry, biology, biochemistry, geology, law, or statistics–can be very important when applying isotope analysis techniques and interpreting the resultant data. The field of isotope forensics is relatively small compared to some other forensic disciplines, so be sure to read papers, attend meetings, and network with scientists working in the field.

Visit the Isoforensics Inc. website for more information.