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•The Megyesi et al. (2005) [1] method overestimated the PMI of remains.•The Vass (2011) [2] method underestimated the PMI of remains.•Methods estimated the PMI within 2 weeks in the fresh stage of decay.•Geographic specific PMI methods are required for Australian environments. Forensic anthropologists have traditionally relied on their knowledge and experience of the decomposition stages to make an assessment of the time since death. However, recently new and empirical methods have been developed in various regions worldwide that propose to estimate the post-mortem interval (PMI) based on the observed decomposition changes alongside important taphonomic variables. Yet despite these methods being predominantly geographic specific, a number of methods have suggested they are effective universally and it is these ‘universal’ methods that have been inadequately test in Australia. The current study evaluated the accuracy of two of these methods in an Australian context, specifically the Greater Western Sydney region. The protocol developed by Megyesi et al. (2005) [1] was investigated because it is commonly cited in the literature and the PMI formula created by Vass (2011) [2] was also investigated because of its ‘universal’ claim. Between December 2014 and March 2016, two experimental trials were undertaken during the Australian summer seasons. Sixteen adult pig carcasses were left to decompose undisturbed on a soil surface common throughout the Western Sydney region and the Megyesi et al. (2005) [1] and Vass (2011) [2] methods were applied to the remains during this period. The results showed the Megyesi et al. (2005) [1] method overestimated the known PMI of remains, whereas the Vass (2011) [2] formula underestimated the time since death of the remains in these trials. The inaccuracy may be attributed to the constants which make up the variables in these formulas and they may not reflect the values of these variables in the Western Sydney region.

•Movement of human remains through the underlying soil and sediment were monitored.•Vertical leaching was detected up to a depth of 49cm below the ground surface.•The greatest extent of vertical penetration was found directly beneath the torso.•Lateral leaching was detected 2.5m from the torso centre; distance may be further.•Methodology and data can be applied to environmental monitoring and forensic casework. Due to the lack of human decomposition research facilities available in different geographical regions, the extent of movement of human decomposition products from a cadaver into various sedimentary environments, in different climates, has not been able to be studied in detail. In our study, a human cadaver was placed on the surface of a designated plot at the Australian Facility for Taphonomic Experimental Research (AFTER), the only human decomposition facility in Australia, where the natural process of decomposition was allowed to progress over 14days in the Australian summer. Sediment columns (approximately 1m deep) were collected at lateral distances of 0.25m, 0.5m, 1.0m and 2.5m in each of four directions from the centre of the torso. Plot elevation and weather data were also collected. Each sediment column was subdivided, dried and homogenised. A sample was isolated from each sediment subdivision, extracted with hexane, and the hexane extract cleaned with citrate buffer (pH 3), filtered and spiked with cholesterol-D7 internal standard. After derivatisation with BSTFA+1% TMCS, cholesterol was monitored in the samples using targeted gas chromatography tandem mass spectrometry analysis. A positive result for decomposition products was given if the cholesterol abundance in the test sample was higher than that detected in the ‘control’ samples of a similar substrate type collected prior to cadaver placement. Within the confines of the experimental design and the measured parameters, lateral leaching was observed over distances of up to 2.5m from the centre of the torso, which was the maximum distance tested in the study. Vertical leaching was detected to depths of up to 49cm below the ground surface. Such data can aid the development of policies related to plot sizing and sediment renewal and regeneration at other human decomposition facilities and at cemeteries. The density and distribution of cholesterol surrounding the cadaver in this study can also help forensic investigators interpret cases involving remains that have been moved or scavenged.

Human taphonomic facilities (HTF) are outdoor spaces dedicated to research, educational and training activities related to human decomposition. Through the purging of decomposition by-products, a body within a HTF will generate a chemically and microbially disrupted zone of soil known as a Cadaver Decomposition Island (CDI). The biochemical dynamics of CDIs have been minimally investigated across contrasting seasons, thereby impeding our understanding of how cadaveric inputs are processed within temperate soils. This gap was addressed in a Canadian HTF by examining soil organic matter (SOM) chemistry and bacterial metabolic responses within the CDIs of donors bodies who were deposited under warm or cold seasonal conditions. Decomposition generated a pulse of SOM that was first rich in carbon then nitrogen. This was associated with an enrichment in δ13C and δ15N that was attributable to cadaveric tissues and enhanced mineralization. Fluorescence spectroscopy also revealed a transition in the molecular characteristics of organic matter that was indicative of a shift from recalcitrant terrestrial substances to labile microbial compounds. In addition, bacteria were observed to preferentially utilize carbohydrate substrates for energy production. These effects arose during the Active–Dry phases of decomposition, occurring between 13–139 days for warm deposited donors, but were delayed (31–364 days) and reduced in magnitude for cold donors. All changes were limited to the A-horizon and within a sampling radius of 20 cm from the body. These findings will inform temperate HTFs of their potential environmental impact and direct the development of soil-based forensic techniques. •Effect of human decomposition on soil biochemistry was spatially constrained.•Increases in soil carbon preceded nitrogen.•Bacterial processing altered soil organic matter lability.•Cadaveric inputs enhanced bacterial mineralization but supressed growth.•Cold season deposition led to delayed and reduced soil changes, even after warming.

•Two simulated building collapses were created to investigate a unique decomposition environment.•Location of the bodies in the disaster area greatly impacted the state of decomposition.•The VOC profiles emitted from the disaster area changed over time.•Several VOCs attributed to the decomposition of remains were determined. [Display omitted] The occurrence of mass disasters has increased worldwide due to changing environments from global warming and a heightened threat of terrorism acts. When these disasters strike, it is imperative to rapidly locate and recover human victims, both the living and deceased. While search and rescue dogs are used to locate the living, cadaver detection dogs are typically tasked with locating the dead. This can prove challenging because commingling of victims is likely to occur during disasters in populated areas which will impact the decomposition process and the resulting odour produced. To date, there has been no research to investigate the process of human decomposition in a mass disaster scenario or to understand which compounds are detectable by cadaver detection dogs. Hence, the current study investigated the human decomposition process and subsequent volatile organic compound (VOC) production in two simulated building collapse scenarios with six human donors placed in each scenario. The human remains were only recovered after a period of one month, during which time VOC samples were collected and analysed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. A considerable degree of differential decomposition was observed upon recovery of the human remains, which was carried out as a part of a police disaster victim recovery training exercise. The location of the bodies in the disaster area was found to impact the decomposition process. The VOC profile was found to correlate with the decomposition process. Fifteen days following the simulated disaster, the VOC profile changed showing that a detectable change in the decomposition process had occurred. Overall, the changing VOC profile can inform the training of cadaver detection dogs for these unique scenarios.

Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.

Abstract Forensic entomology has been developing globally for decades. Despite this discipline being used in criminal investigations around the world, only a few controlled studies have been performed on human cadavers in human decomposition facilities, with the majority of these being conducted in warm and often dry climates. Therefore, the purpose of our research was to catalogue the first published data on insects associated with decomposed human bodies in a humid, continental (Dfb) climate. Specifically, our objective was to document the diversity and succession of the entomofauna associated with human cadavers throughout the decomposition process, in the Quebec province of Canada, during the summer season. Two human cadavers were studied in 2020 at the site for Research in Experimental and Social Thanatology, REST, located in Bécancour (Quebec, Canada). Insects (and other arthropods) were regularly sampled by visual observations, collection from the cadavers, and by using an entomological net and pitfall traps. Our results highlight that the decomposition process is a heterogeneous and complex process in Quebec, with cadavers showing signs of precocious desiccation/mummification. In addition, our observations confirm that the presence of superficial skin lesions accelerates the colonization of blow flies (Diptera: Calliphoridae) and, consequently, the process of decomposition. Finally, we were able to discriminate between “early colonizers” (e.g., Calliphoridae Lucilia sp. or Calliphora livida), “late colonizers” (e.g., larvae of Piophilidae or Heleomyzidae), and “non-specific colonizers.” We also officially report the first observation of Cochliomyia macellaria (Diptera: Calliphoridae) in Quebec. These findings will provide new information to help medico-legal death investigations by determining the minimum time elapsed since death and the circumstances surrounding death.

Forensic taphonomy investigates the postmortem processes of human remains, focusing on the environmental factors that influence decomposition. Recent studies have highlighted the potential forensic relevance of fungi in this context, but the knowledge base remains limited. This study explored fungal communities associated with outdoor human decomposition at the REST[ES] facility in Quebec. Nested PCR amplification and Illumina MiSeq sequencing were used to identify fungal species on discolored patches of twelve samples of desiccated soft tissues from three donors. Twelve fungal species were putatively identified, some of which were previously unknown on human remains, including Leucosporidium yakuticum, Tausania pullulans, and Fusicolla species. These fungi may contribute to tissue discoloration and following longitudinal investigation, could serve as biomarkers for forensic reconstructions, including place and time of death. This study emphasizes the need for further research into the role of fungi in human decomposition processes and their applications in forensic science. •We identified the first fungal species associated with human decomposition in Quebec.•Twelve fungal species were identified, some previously unknown on human remains.•The molecular identification of fungi avoided bias toward only culturable species.

Taphonomy is the study of decaying organisms over time and their process of fossilization. Taphonomy, originally a branch of palaeontology and anthropology, was developed to understand the ecology of a decomposition site, how site ecology changes upon the introduction of plant or animal remains and, in turn, how site ecology affects the decomposition of these materials. In recent years, these goals were incorporated by forensic science to understand the decomposition of human cadavers, to provide a basis on which to estimate postmortem and/or postburial interval, to assist in the determination of cause and circumstances of death, and to aid in the location of clandestine graves. These goals are achieved through the study of the factors that influence cadaver decomposition (e.g. temperature, moisture, insect activity). These studies have also provided insight into the belowground ecology of cadaver breakdown and allowed to develop useful protocols for mass disaster managements in humanitarian medicine. From the results obtained, new scientific disciplines have arisen, gathered under the word “taphonomics” such as the study of microorganisms living below/on a cadaver (thanatogeomicrobiology), and join the more classical forensic sciences such as anthropology, botany or entomology. Taking into account the specificities of the study object (human cadaver), primordial requirements are needed in terms of security (physical and environmental) as well as ethical and legal concerns which are studied in the Swiss context. The present review aims to present in a first part the concept of human forensic taphonomy facilities (HFTF, also colloquially named “body farm”) leading to an enrichment of forensic sciences with new “taphonomics”. The second part is focused on the mandatory points that must be addressed for a HFTF approach, especially because it requires a specific place to undertake this research which must be performed in conformity with a country’s human ethics and laws.

The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography--time-of-flight mass spectrometry (GC × GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC × GC-TOFMS were demonstrated for detecting and identifying trace levels of VOCs, particularly ethers, which are rarely reported as decomposition VOCs.

After death, the human body undergoes various processes that result in the emission of volatile organic compounds (VOCs). The interest in these VOCs has increased substantially in recent years because they are key attractants for necrophagous insects and vertebrate scavengers. Identifying cadaveric VOCs has required the effective development of analytical tools for collecting, separating, identifying, and quantifying the suite of VOCs released throughout decomposition. Analytical developments for studying cadaveric VOCs in vertebrates, ecological interactions of cadaveric VOCs with the abiotic and biotic environment, and the necessity for convergence of these two areas for the progression of future knowledge are discussed herein.