Research

The DETECT Laboratory at the University of Windsor undertakes research in forensic taphonomy and decomposition chemistry. We do this by studying the chemical processes of death, decomposition, and how this knowledge applies to scent-detection dogs.

Taphonomy aims to understand the events and processes that effect the remains of an organism following death. Traditionally, it has been used to study the transition of organic remains into the fossil record. In a forensic context, taphonomy is used to define all agents that affect human remains between death and discovery.

Forensic taphonomy involves the use of taphonomic approaches to estimate time since death, reconstruct the events surrounding death including pre- and post-burial, and identify bone modifications resulting from taphonomic factors.  Forensic taphonomists are also concerned with the rates and patterns of soft tissue decomposition.  Research in the field of forensic taphonomy must therefore focus on the effects of taphonomic agents on both soft and hard tissue in a range of environments. Influencing factors may include temperature, moisture, clothing, soil type, trauma, biomass, deposition site, and other environmental conditions.

One of the main challenges in forensic taphonomy today is understanding how postmortem changes to human remains will affect the estimation of time since death. In our laboratory, we are addressing this question using decomposition chemistry.

Decomposition chemistry is an emerging field of forensic taphonomy that studies the degradation pathways in a body postmortem. The biochemical degradation of soft tissue involves the disintegration of cells and the release of lipid, protein, carbohydrate, and nucleic acid products to the environment. Analysis of these by-products using advanced chromatographic and spectroscopic techniques over time has the potential to identify organic markers that correlate with the postmortem period. In the future, we hope this information can be used to estimate time since death of decomposed remains more accurately.

The aim of my current research program is to characterise new chemical markers of soft tissue decomposition in the distinct cold climate of Canada. Currently, there is little decomposition data from climates that incorporate extreme temperatures (ranging from +40°C to -40°C), and the research that has been conducted is exclusively on pig carcasses. The study of decomposition using cadavers has only been conducted in milder regions of the USA and Australia with recent data suggesting that pigs are not directly comparable to human decomposition. Our research conducted at northern-latitude human decomposition facilities is allowing the first controlled decomposition studies to be performed in cold climates using donated cadavers.

The biochemical degradation of soft tissue releases a range of liquefied and gaseous products into the surrounding environment. Products released into the air and soil include the volatile organic compounds (VOCs) that are used by cadaver-detection dogs to locate human remains. Our research involves trapping those VOCs and chemically identifying them to produce a decomposition odour database. Key VOCs recognised to be statistically-relevant in this database are verified during training with police cadaver-detection dog units. It is hypothesized that dogs do not locate a single compound, but rather a suite of VOCs. Our research is attempting to identify the suite of compounds that is unique to human decomposition odour. It is particularly important to understand how cadaver-detection dogs locate these VOCs in extremely cold climates such as Canada. Ultimately, our research assists to enhance their training and success in locating victim remains.

Given the invaluable contribution made by those who donate their bodies to human decomposition facilities, it is imperative that we collect as much data as possible from every donation. To ensure this requirement, all of our methods are first developed, optimised and tested using animal research models (e.g. porcine remains). The methods include collection of soft tissue, odour, entomological samples, bacterial swabs, soil samples, vegetation, imagery of vertebrate scavengers, and ultimately bones. The porcine remains are placed in a fenced area belonging to the University of Windsor to ensure decomposition is being monitored in our microclimate. The FARM also allows for comparative studies to be conducted to determine the similarities and differences in decomposition processes between human and other animal remains.

The DETECT Laboratory houses a LECO Pegasus^® BT 4D two-dimensional gas chromatography – time-of-flight mass spectrometer (GC×GC-TOFMS). All chemical analyses in our laboratory are carried out using this advanced instrumentation. Although decomposition biochemistry has traditionally been investigated using gas chromatography-mass spectrometry (GC-MS), our research has demonstrated that GC×GC-TOFMS provides superior analysis for the identification of decomposition biomarkers in air and soil. Due to the complexity of the decomposition process and the hundreds to thousands of compounds that can be produced by decomposed remains, an advanced GC system is required to ensure we adequately separate and accurately identify key compounds.

Photo credit: Josée Beaulieu