May 12, 2019 by Locard's Lab

Detecting Homemade Bombs & Explosives in Sweat

Improvised explosive devices (IEDs) are often used in the implementation of terrorist attacks, for instance the 2005 London underground bombings, the suicide bomb attack during a concert in Manchester, and the 2015 Paris attacks. Unfortunately the components required for building these devices are commercially available and the bombs relatively easy to construct.

Many explosives leave a characteristic trace after being handled or detonated, and it is essential that investigators can rapidly identify the components used in homemade explosives. Furthermore, the ability to trace the explosives back to particular individuals and terrorist cells is essential in preventing future attacks. Unfortunately effectively detecting and tracing explosives and explosive precursors can prove difficult. On top of this, after the production and implementation of IEDs, it can be difficult to prove a suspects’ involvement in bomb construction.

Researchers at King’s College London and Northumbria University have been working on developing new ways to detect homemade explosives.

The newly developed approach, recently published in the journal Analytica Chimica Acta, uses a technique known as ion chromatography high resolution mass spectrometry (IC-HRMS) to separate and detect chemical components. By applying the technique to compounds commonly encountered in the analysis of explosive residues, the method was shown to be effective in detecting a large number of components used to make bombs, capable of detecting just trace amounts of the chemicals faster than previous techniques.

Upon developing this method, the team of researchers then demonstrated that the approach could be applied to the analysis of human sweat, with the aim of indicating an individual has recently handled explosives. Participants were made to handle Pyrodex powder, a black powder propellant used in firearm cartridges. After handling the powder for a few minutes, palm sweat and fingermark samples were then collected at numerous timepoints over several hours. Analytes related to the explosive material were readily detected using the method. The real-world implementation of this technique could help prove contact between a suspect and explosive material or explosive precursors.

Gallidabino et al. Targeted and non-targeted forensic profiling of black powder substitutes and gunshot residue using gradient ion chromatography – high resolution mass spectrometry (IC-HRMS). Analytica chimica acta. 2019, In Press.

March 22, 2019 by Locard's Lab

Developing Fingerprints on Metals to Aid Knife & Gun Crime Investigations

Fingerprints are something of a staple in forensic science. For over 100 years we have used the unique details of fingerprints to identify victims and suspects, and draw connections between people and objects to place suspects at crime scenes. Fingermarks are encountered on all kinds of surfaces that can have an effect on how easy it is to visualise the mark and for how long the mark persists. As a result, the market is flooded with products for developing fingerprints, from powders to glues to chemical reagents.

Despite the options available, some surfaces, for instance metals, still prove somewhat tricky when it comes to developing prints. This is due to various factors, such as how the chemical results in the fingermark and developing reagents may react with the surface. This is obviously problematic when trying to obtain fingerprints from knives and firearms, a matter of particular importance right now worldwide. For years researchers have been examining methods of improving the detection of fingerprints on metals, including metal vapour deposition and different chemical reagents, but reliable techniques are still few and far between.

Researchers at the University of Nottingham and University of Derby in the UK are using analytical chemistry to solve this problem. Using a technique called Time-of-Flight Secondary Ion Mass Spectrometry, or ToF-SIMS, researchers have developed a way of producing images of fingerprints of various metal surfaces. ToF-SIMS utilises an ion beam which is passed along the surface of the sample, causing ions (charged chemical components) to be emitted from the sample. These are then analysed by mass spectrometry and the results used to produce a kind of map of the surface.

Researchers deposited fingermarks on various types of commonly-encountered metals, such as stainless steel and aluminium, and studied the effects of time on the ability to visualise the prints. Cyanoacrylate (or superglue) fuming, a traditional technique particularly popular when analysing metal surfaces, proved to be unreliable, with the print’s quality degrading rapidly or disappearing completely in just a matter of days. However using this new mass spectrometry-based approach, fingermarks could be visualised in samples up to 26 days old, a vast improvement on traditional methods.

The high-resolution images produced sufficient detail to not only observe ridge detail in the marks, but even the shape and position of individual sweat pores. Furthermore, and perhaps most importantly in a forensic context, the technique is non-destructive. Current methods of visualising fingerprints tend to involve adding a powder or chemical to the print, inevitably altering and potentially contaminating it. But the use of ToF-SIMS ensures the print remains intact, so further development or analysis techniques can be employed if required.

By enabling the visualisation of fingerprints that previous techniques may have failed to reveal, this method has the potential to not only aid investigators as they face the ongoing rise of knife and gun crime, but could also be applied to cold cases. However it is important to note that fingermarks deposited as part of research are not always indicative of real-world samples. In reality the fingerprints we leave behind can vary greatly in the amount of material deposited and the type of material being left behind. Traces of anything handled can be deposited in the fingermark, adding many potential variables to the real-world applicability of this kind of work. Despite this, the study demonstrates a promising new technique for the development of fingermarks on metals, which could have great implications in the investigation of violent gun and knife crimes.

Thandauthapani et al. Exposing latent fingermarks on problematic metal surfaces using time of flight secondary ion mass spectroscopy. Science & Justice. 2018, 58(6).

February 8, 2019 by Locard's Lab

Tracking Movements with Fingernails

When human remains are discovered, investigators will often turn to routine methods such as fingerprinting, DNA profiling and the use of dental records to identify the individual. But in the absence of database records for comparison, such traditional techniques may not prove all that useful, and forensic scientists must look for new ways to identify the unknown.

In recent years the use of stable isotope analysis has aided forensic investigations, particularly in establishing the geographic origin of unidentified human remains. Isotopes are different forms of an element. For example, oxygen has three naturally occurring stable isotopes: O¹⁶, O¹⁷ and O¹⁸. These isotopes are incorporated into substances in the environment (such as water) in varying ratios. The relative abundance of isotopes can be influenced by various factors in a process known as isotopic fractionation. It has been found that isotopic ratios can be related to different regions of the world. For example, the tap water in one country may have a completely different isotopic signature in comparison to water in another country. How does this relate to the isotopes found in our bodies? Well, you are what you eat. As you consume food and water from a particular area, the atoms in our bodies express abundances similar to the food and water consumed.

This provides the basis for using isotope analysis to trace materials back to a certain geographic region. It has already been demonstrated that the isotopic analysis of bones, teeth and other bodily tissues can allow for individuals to be traced to particular locations, typically through the analysis of oxygen, hydrogen and sulphur isotopes. However last year, researchers at the University of Utah took a different approach, this time focusing on fingernails.

As with bones and teeth, the isotopic content of our fingernails will be affected by factors such as the food and water we consume. As fingernails are estimated to grow at a rate of 3-4mm per month, they are a prime target for studying isotopic patterns in an individual over a shorter timespan (less than six months as oppose to years). This is by no means the first study of isotope abundances in fingernails, but previous research has typically focussed on single timepoints rather than tracking the same individuals over time. As global travel becomes more commonplace, it is increasingly likely that human remains could have originated from any part of the world. Therefore, we need to understand how travel can cause changes in isotope abundances within the body.

This study aimed to establish whether fingernail isotope ratios were different in a group of local people in comparison to non-locals who had recently moved to the area (in this case Salt Lake City in the United States). Over a period of a year, fingernail clippings were collected at multiple timepoints from a group of volunteers, about half of which were local residents and the rest individuals who had recently arrived from various locations across the US and the world. The fingernail clippings were cleaned (to remove surface components and contaminants that could interfere with the analysis) and subjected to analysis by isotope ratio mass spectrometry (IRMS). IRMS is a particular type of mass spectrometry that allows us to measure the isotopic abundance of certain elements typically hydrogen, carbon, nitrogen, and oxygen. You can read more about IRMS here.

The isotope values of samples from residents were used to construct a baseline of expected values for the area, with isotope values from non-residents’ samples being compared with these. Initially, samples from non-residents showed a wide range of isotopic values, which is to be expected given they had only recently moved to the area. Some residents did fall within the expected range of locals, but these participants had moved from relatively nearby locations, which could explain the similar relative isotopic abundances. However after about 3 months, the fingernail isotopic patterns shifted until the non-residents could no longer be distinguished from the residents. This indicates that although the relative abundance of isotopes in our fingernails can shed some light on geographical movement, it can only provide information relating to the past few months. Inevitably there will always be a certain amount of error associated with such analyses, with variation from the likes of short-term travel and random dietary changes being impossible to account for.

Mancuso, C. J, Ehleringer, J. R. Resident and Nonresident Fingernail Isotopes Reveal Diet and Travel Patterns. Journal of Forensic Sciences. 2019, 64(1).

December 3, 2018 by Locard's Lab

Interview with Forensic Taphonomist Professor Shari Forbes

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

Forensic taphonomist Professor Shari Forbes.

I am a Canada 150 Research Chair in Forensic Thanatology and the Director of the Secure Site for Research in Thanatology (SSRT). The SSRT represents the first human taphonomy facility in Canada and is the only place in this distinct climate where we can study the process of human decomposition through body donation. My role is to lead and conduct research at this facility, specifically in the field of forensic thanatology and decomposition chemistry. This role also involves engaging collaboratively with our external partners who can benefit from the research and training we conduct at the facility, notably police, forensic services, search and rescue teams, military, human rights organisations, and anyone involved in death investigations.

What initially attracted you to your particular field of research?

I have always had a passion for science and knew that I wanted to pursue a career in a scientific field where I could clearly see the impact of my work. When I was in high school, I enjoyed reading crime novels and probably understood what forensic science entailed better than most people (this was before the advent of CSI, Bones, NCIS, etc.!). My love of science combined with my interest in criminal investigations naturally led to pursuing a career in this field. At the time, there was only one university in Australia that offered a forensic science degree so the decision of where and what to study was relatively easy. Although chemistry wasn’t my strongest subject at school, I enjoyed the degree because it applied chemistry to forensic science and in this way, I could understand how my skills would help police investigations.

Can you tell us about the research you’re currently involved in?

My research focuses on the chemical processes of soft tissue decomposition and the by-products released into the environment. This can include compounds released into air, water, soil, textiles, or anything surrounding the body. The majority of my research at the moment focuses on the release of volatile organic compounds (VOCs) into the air to better understand the composition of decomposition odour. Although this is not pleasant work, it is very important to understand the key compounds used by cadaver-detection dogs for locating human remains. If we can identify the key VOCs and determine when they are present, we can enhance the training and success of cadaver-detection dogs in complex environments such as mass disasters.

You were heavily involved in the establishment of the Australian Facility for Taphonomic Experimental Research. What were some of the greatest challenges in this and how has the facility since developed?

It took approximately 3.5 years to establish AFTER from the day we started planning it to the day it opened in January 2016. I have since realised this is not that long compared to some of the other facilities that are currently operating but there were challenges and hurdles that we faced along the way. In Australia, establishing a human taphonomy facility essentially requires three things: 1) an organisation willing to lead and support it; 2) a body donation program; and 3) accessible land that can be used for taphonomic research. We were fortunate that the University of Technology Sydney (UTS) had these three things and we also had the financial and in-kind support of all of our partners including academic institutions, police services and forensic laboratories. Once we had this support and made the decision to proceed, we still needed to seek approval from our local council to use the land for this purpose; apply for funding to build the facility; and apply to have the facility licenced to hold human remains for the purposes of taphonomic research and training. Thankfully, everyone we engaged with was highly supportive of the facility and willing to work with us to ensure we followed all legislation and regulations. We also ensured we had a strong communication plan to raise awareness with the general public about the benefits of these facilities and how important the research is to assist in the resolution of death investigations.

The Australian Facility for Taphonomic Experimental Research

Since opening, we have been amazed by the general interest in AFTER and the number of people wanting to donate their body. We have also increased our partnerships to benefit more police and forensic services as well as others services such as the cemetery industry. We are currently planning to provide more training opportunities, particularly relating to disaster victim recovery and identification, and to establish more AFTER facilities across Australia to better represent the diverse climates experienced across the country.

You recently left the University of Technology Sydney to relocate to Canada. How will your role and research be changing as you make this move?

I was honored to be the Director of AFTER and it was a difficult decision to leave Australia. However, I recognise the importance of these facilities and the need to establish them in other countries so when I was asked to open Canada’s first human taphonomy facility, it was an opportunity I could not turn down. My experience in Australia has already assisted greatly in establishing the facility in Quebec and we will certainly be able to open the facility much more rapidly as a result. Like in Australia, we hope it acts as a template for future facilities across Canada since this country also has very diverse climates. In reality, neither my role nor my research will change significantly. The greatest change will be the climate and its impact on the process of decomposition!

Finally, do you have any advice for young scientists eager to pursue a career in your field of work?

It sounds like a cliché, but I always encourage students to pursue a career in a field they are passionate about. If you had told me 20 years ago that I would being leading not one, but two ‘body farms’ I would never have believed it (especially after just reading Patricia Cornwell’s novel that gave these facilities that name!). But I knew I was passionate about studying a science that was deeply applied and had a clear impact on society. I had no idea where it would lead me or even if I would get a job in the field, but without that passion, I would not have been motivated to do any of the things I have done; namely: complete my degree, continue on with a PhD, do research in decomposition chemistry, and ultimately become an academic so that I could continue my passion of conducting forensic taphonomy research. So if you are going to do something for the next fifty years, make sure it is something you love doing!

Find out more on the Secure Site for Research in Thanatology website.

This is Part 17 of our series of interviews with forensic professionals. If you’re a forensic scientist (academic or industry) or a crime scene investigator and would like to be part of this series of interviews, get in touch by emailing locardslabblog[at]gmail.com.

October 22, 2018 by Locard's Lab

Drug Detection at Your Fingertips: Illicit Drugs in Fingerprint Sweat

Researchers have developed a new tool for the rapid detection of a number of illicit drugs using only the sweat of an individual’s fingerprint.

Typically, the procedure to test for drugs in human beings necessitates the collection of blood or urine and laboratory-based analysis by gas or liquid chromatography with mass spectrometry. Unfortunately these standard methods are somewhat invasive, require potentially time-consuming laboratory-based analysis, and use complex pieces of analytical instrumentation requiring a trained operator to use. They are inevitably unsuitable for rapid, in-situ screening of potential drug users.

Researchers at the University of East Anglia and Intelligent Fingerprinting Ltd (a spin-out company from the university) have been working on a method of conducting simple, rapid drug analysis using sweat from a person’s finger. The technique has been developed to detect four classes of drugs – cannabis, cocaine, amphetamines and opiates, with cannabis being detected based on the presence of Δ⁹-tetrahydrocannabinol (THC), cocaine on the presence of benzoylecgonine, and opiates via the detection of morphine.

The finger of an individual is firmly pressed onto the Drug Screening Cartridge. This is then filled with a buffer solution before insertion into the reader for analysis. Capable of detecting drugs down to the picogram level, the system is a fluorescence-based lateral flow competition assay containing four drug-bovine serum albumin conjugate lines on a nitrocellulose test strip. In short, when a sample is introduced to the test strip, fluorescently-tagged antibodies pass over the conjugate lines. As these antibodies are specific to each drug class of interest, if that drug is present they will bind to the drug. At the end of the test, a fluorescence signal is measured. If none of the four drug classes were present, a maximum fluorescence signal will be obtained. However if any drugs were present to bind with the antibodies, there will be a decrease in the fluorescence signal proportional to the drug concentration. Within about 10 minutes, the device then gives a simple pass/fail response, requiring no specialist knowledge or excessive training to operate and interpret the results.

Furthermore, the technique has also been demonstrated to be effective when applied to the deceased. Researchers worked with a number of UK-based coroners to obtain fingerprint sweat samples from 75 deceased individuals. The most common drug detected was opiates, which is a logical finding considering the number of terminally ill patients who are prescribed morphine during palliative care.

In order to compare the new technique with those typically employed in the detection of drugs in human beings, analysis of blood samples was conducted by LC-MS-MS. The results between the two methods correlated well, with the accuracy between DSC of fingerprints and LC-MS-MS of blood being 88-97%, depending on the drug. This demonstrates the effectiveness of the method and its ability to stand up to existing techniques, though there are inevitably some shortcomings. Authors of the study have stated that there are known accuracy issues with lateral flow measurement devices, thus this new technology should be used as a presumptive screening method prior to confirmation by mass spectrometry. Furthermore, the range of target drugs is clearly currently limited, though future development could no doubt enable other classes of drug to be included.

Full details of the findings can be found in the Journal of Analytical Toxicology.

References

Hudson, T. Stuchinskaya, S. Ramma, J. Patel, C. Sievers, S. Goetz, S. Hines, E. Menzies and D. A. Russell, J. Anal. Toxicol., 2018, 6–10.

Forensic Magazine. Fingerprint Drug Screen Test Works on the Living and Deceased. [Available online] https://www.forensicmag.com/news/2018/10/fingerprint-drug-screen-test-works-living-and-deceased

May 21, 2018 by Locard's Lab

Forensic Failures: Philip Scott Cannon & Bullet Analysis Blunders

In December 2009, Philip Scott Cannon of Polk County, Oregon was released from prison after his conviction was found to be based on ‘junk science’. By this time, he had served over 10 years.

The story of his wrongful imprisonment began on 23^rd November 1998, when Bimla Boyd noticed that the mobile home of a neighbour appeared to be on fire. Upon investigating, she discovered the bodies of three people; Jason Kinser, his girlfriend Suzan Osborn, and Celesta Graves. All three victims had been shot. Boyd promptly called the police, and a murder investigation ensued.

Boyd stated that earlier in the day she had noticed a maroon van parked nearby, a van which happened to belong to Philip Scott Cannon. Around the same time, local men Jeremy Olsen and Larry Weaver were on their way to deliver water to the victims’ trailer. Upon arrival at the trailer, Olsen and Weaver claimed that they were met by Cannon, who was said to be “acting strangely”. Cannon informed the men that they should not go into the trailer because Jason Kinser was upset and in the midst of a heated argument with an unknown Hispanic man. Olsen and Weaver subsequently left without entering the trailer. Based on this eyewitness testimony and the fact that Cannon owned the maroon van spotted nearby, he soon became the prime suspect.

Credit: Polk County Itemizer-Observer

When questioned by police, Cannon maintained his innocence and claimed Kinser had called him over to give an estimate for fixing a plumbing problem in the trailer, after which he promptly left when Kinser began arguing with another man. However the police had a very different impression of the situation, believing that Cannon was a meth user and Kinser his dealer. Further suspicion fell on Cannon when a prisoner, Steven Brobston, informed police that he had entrusted Cannon with a box containing $16,000 to be used to support Celesta Graves, Brobston’s girlfriend and one of the victims. With the circumstantial evidence mounting, investigators searched Cannon’s home, finding the lockbox but no sign of the money. They did however stumble upon a number of weapons and ammunition. This was sufficient to arrest Cannon, who was taken into custody on 3^rd December and charged with three counts of aggravated murder and the illegal possession of a firearm.

During the trail, Olsen, Weaver and Boyd were all called upon to recount their experiences of seeing Cannon near the trailer on the day of the murder. Of course this evidence was purely circumstantial, so an expert witness was called upon to study the bullets collected from the crime scene and those recovered from the suspect’s home. Michael Conrady of Oregon State University’s radiation center conducted a metallurgic analysis of the bullets known as comparative bullet lead analysis. This technique involves the application of various analytical techniques, but primarily atomic emission spectroscopy, to bullet composition determination. The method aims to establish the composition of metals in the bullet, such as copper, tin, antimony and silver, and compare profiles to ascertain whether two bullets are chemically identical. Based on this analysis, Conrady testified that the bullets from the crime scene and those from Cannon’s home were chemically identical, therefore Cannon’s ammunition was used to kill the three victims. However the weapons found in Cannon’s home were not connected to the murders, nor did police establish a reasonable motive for the triple homicide. Despite these shortcomings, on 28^th February 2000, Cannon was found guilty and sentenced to three life sentences with no parole.

At the time of Cannon’s trial, the use of comparative bullet lead analysis was already under scrutiny, with some believing the reliability of the technique was unfounded. In 2005, the national Academy of Science discredited the technique and deemed it ‘junk science’, and soon after the FBI abandoned the use of this method altogether. As Cannon’s conviction was so heavily reliant on the bullet analysis, in 2009 a Polk County Circuit judge vacated Cannon’s original conviction. Incidentally it was now apparent that police involved in the original trial had hired Conrady to conduct the bullet analysis because the Oregan State crime lab had refused on the basis of the technique being scientifically unreliable. In order for a re-trial to take place, the original bullets were demanded in order to conduct further analysis. Polk County prosecutors insisted that the original trial evidence had been sent to the Department of Justice when Cannon had appealed his conviction, however Assistant Attorney General Susan Gerber, who had been assigned the case, claimed she had never received this evidence. It later came to light, when Gerber was suspended from her position on assault charges, that she had had the evidence all along, locked away in a filing cabinet.

In light of all of this, Cannon’s conviction was dismissed and he was released from prison. By this point he had spent over a decade behind bars. No other arrests have been made in relation to the murder of Kinser, Osborn and Graves.

References

Michigan State University National Registry of Exonerations. Philip Scott Cannon. [Available online] https://www.law.umich.edu/special/exoneration/Pages/casedetail.aspx?caseid=3083

Photo Credit: Polk County Itemizer Observer. Cannon retrial up to Polk DA. [Available online] http://www.polkio.com/news/2011/oct/25/cannon-retrial-up-to-polk-da

April 4, 2018 by Locard's Lab

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

November 28, 2017 by Locard's Lab

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.

November 22, 2017 by Locard's Lab

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.

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).

August 9, 2017 by Locard's Lab

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.

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).