Anthropology Research Facility Research Articles

Using Stable Nitrogen Isotope Ratios from Human Skeletal Muscle Tissue for Postmortem Interval (PMI) Estimation (Part 1)

Human skeletal muscle tissue was analyzed for stable nitrogen isotope analysis (δ15N) to test the applicability of changes in values (Δ15N) through the putrefaction process for postmortem interval (PMI) estimation. Seasonal differences in Δ15N values of decom-posing skeletal muscle tissue were analyzed from 20 human donors at the University of Tennessee Anthropology Research Facility. This study revealed that change in the δ15N ratios of decomposing muscle tissue has potential as a novel method for PMI estimation. In winter months, when identifiable muscle tissue can be retained on a body for months, the data indicate that there is a systematic increase in Δ15N values with increasing temperatures when putrefaction progresses faster with values shifting as much as 3.0‰. This initial study indicates there is value in further method development of this quantitative approach to PMI estimation for recently deceased individuals, but further work is needed. While the analysis only requires a small amount of tissue, has a user- friendly collection and analysis protocol, and is less subjective than visual methods, there is still significant research to be done prior to widespread applications as a PMI estimation method. Understanding variability in δ15N across decomposing muscle tissue groups, individual variation (i.e., muscle mass, disease, body chem-istry), and an accurate approximation for a perimortem δ15N value necessary to calculate Δ15N all need to be further researched prior to generation of a reliable regression formula and error rates.

Human decomposition in the unique context of the Andaman and Nicobar Islands (India): a comparative analysis with reference data

ABSTRACT The understanding of the victim’s decomposition process is crucial in forensic science for establishing accurate time since death, and the overall timelines of criminal investigations. Global research, which primarily relies on non-human animal proxies, highlights a scarcity of facilities using human bodies and a lack of baseline data for some regions and remote locations. In cases such as the Andaman and Nicobar (A&N) Islands (India), forensic practitioners turn to literature-derived patterns developed at the closest locations (mostly mainland India). This study examines 51 human decomposition cases investigated in A&N in comparison with the existing literature, emphasizing distinctions and similarities in their decomposition relative to the current Indian literature. This study advocates for further research and potentially calls for the establishment of the first anthropology research facility in the Indo-Pacific region, encouraging the development of tailored methodologies for more accurate estimations in diverse environments.

The utility of blow fly (Diptera: Calliphoridae) evidence from burned human remains

Burning of human remains is a common method to conceal or destroy evidence associated with homicides and illegal activities. However, data regarding blow fly colonization of burned remains are scarce, with all previously published empirical studies focusing only on non-human animals. It is critically important to obtain basic data on blow fly colonization patterns of burned human remains as such evidence may represent the only feasible method for PMI estimation in cases of burning. In this study, we thermally altered six human donors to a Crow-Glassman Scale Level 3 (CGS-3) and placed them at the Anthropology Research Facility at the University of Tennessee in Summer 2021, Spring 2022, and Summer 2022. Six unburned human donors were used as controls. Observations for insect activity began within 24 h of placement and continued twice weekly through decomposition. Age estimations were performed with immature blow flies to estimate the time of colonization (TOC), and accuracy was assessed against the time of placement for each donor. All burned donors examined in this study were colonized by blow flies. No significant difference in species composition was determined between treatments, though TOC estimations from burned donors were slightly (but significantly) less accurate than TOC estimations from unburned donors (80% vs. 83% accuracy; χ2 = 0.041, df = 1, P = 0.840). These results indicate that blow flies can successfully colonize human remains burned to CGS-3 and that accurate TOC estimations can still be generated from larval specimens. Though several limitations to this study exist (e.g., inconsistent donor BMI, lack of donor temperature data), our results underscore the utility of entomological evidence in cases of burned human remains.

Soil elemental changes during human decomposition.

Mammalian decomposition provides pulses of organic matter to the local ecosystem creating ephemeral hotspots of nutrient cycling. While changes to soil biogeochemistry in these hotspots have been described for C and N, patterns associated with deposition and cycling of other elements have not received the same attention. The goal of our study was to evaluate temporal changes to a broad suite of dissolved elements in soils impacted by human decomposition on the soil surface including: 1) abundant mineral elements in the human body (K, Na, S, P, Ca, and Mg), 2) trace elements in the human body (Fe, Mn, Se, Zn, Cu, Co, and B), and 3) Al which is transient in the human body but common in soils. We performed a four-month human decomposition trial at the University of Tennessee Anthropology Research Facility and quantified elemental concentrations dissolved in the soil solution, targeting the mobile and bioavailable fraction. We identified three groups of elements based on their temporal patterns. Group 1 elements appeared to be cadaver-derived (Na, K, P, S) and their persistence in soil varied based upon soluble organic forms (P), the dynamics of the soil exchange complex (Na, K), and gradual releases attributable to microbial degradation (S). Group 2 elements (Ca, Mg, Mn, Se, B) included three elements that have greater concentrations in soil than would be expected based on cadaver inputs alone, suggesting that these elements partially originate from the soil exchange (Ca, Mg), or are solubilized as a result of soil acidification (Mn). Group 3 elements (Fe, Cu, Zn, Co, Al) increased late in the decomposition process, suggesting a gradual solubilization from soil minerals under acidic pH conditions. This work presents a detailed longitudinal characterization of changes in dissolved soil elements during human decomposition furthering our understanding of elemental deposition and cycling in these environments.

Sr-Pb isotope differences in pre- and post-burial human bone, teeth, and hair keratin: implications for isotope forensics.

The isotopic signatures of human tissues can provide valuable information on geographic origin for medicolegal investigations involving unidentified persons. It is important to understand the impact of diagenetic processes on isotopic signatures, as alterations could result in incorrect estimation of geographic origin. This study examines alterations in isotope signatures of different tissues of five human body donors studied throughout decomposition at the Forensic Anthropology Research Facility (FARF), San Marcos, TX. Two body donors were buried, two were placed in open pits, and one was first allowed to naturally mummify and then buried. Remains were recovered after a period of 7-34months. The preplacement and post-recovery Sr-Pb isotope data of scalp hair, bone (iliac and tibia), and tooth enamel and dentine were compared. The hair samples record significant shifts in Sr-Pb isotope compositions, with hair keratin Pb isotope composition shifting towards the Pb signature of local soil samples. Hair keratin Sr isotope compositions were altered by the burial environment and possibly also by the lab sample cleaning method. The spongy iliac bone samples show inconsistencies in the recoverability of the preplacement Sr-Pb isotope signatures. The post-placement signatures of the buried donors show slight elevation over preplacement signatures. The post-placement signatures of donors placed in open pits are significantly elevated. The tibia and dental samples record the most consistent isotopic data with the least alteration. These more densely mineralised elements show good recoverability of the preplacement isotope signatures in burials and open pits and are thus deemed better targets for forensic investigative purposes.

The 'ForensOMICS' approach for postmortem interval estimation from human bone by integrating metabolomics, lipidomics, and proteomics.

The combined use of multiple omics allows to study complex interrelated biological processes in their entirety. We applied a combination of metabolomics, lipidomics and proteomics to human bones to investigate their combined potential to estimate time elapsed since death (i.e., the postmortem interval [PMI]). This 'ForensOMICS' approach has the potential to improve accuracy and precision of PMI estimation of skeletonized human remains, thereby helping forensic investigators to establish the timeline of events surrounding death. Anterior midshaft tibial bone was collected from four female body donors before their placement at the Forensic Anthropology Research Facility owned by the Forensic Anthropological Center at Texas State (FACTS). Bone samples were again collected at selected PMIs (219-790-834-872days). Liquid chromatography mass spectrometry (LC-MS) was used to obtain untargeted metabolomic, lipidomic, and proteomic profiles from the pre- and post-placement bone samples. The three omics blocks were investigated independently by univariate and multivariate analyses, followed by Data Integration Analysis for Biomarker discovery using Latent variable approaches for Omics studies (DIABLO), to identify the reduced number of markers describing postmortem changes and discriminating the individuals based on their PMI. The resulting model showed that pre-placement metabolome, lipidome and proteome profiles were clearly distinguishable from post-placement ones. Metabolites in the pre-placement samples suggested an extinction of the energetic metabolism and a switch towards another source of fuelling (e.g., structural proteins). We were able to identify certain biomolecules with an excellent potential for PMI estimation, predominantly the biomolecules from the metabolomics block. Our findings suggest that, by targeting a combination of compounds with different postmortem stability, in the future we could be able to estimate both short PMIs, by using metabolites and lipids, and longer PMIs, by using proteins.

Solving the inverse problem of post-mortem interval estimation using Bayesian Belief Networks

Bayesian Belief Networks (BBNs) can be applied to solve inverse problems such as the post-mortem interval (PMI) by a simple and logical graphical representation of conditional dependencies between multiple taphonomic variables and the observable decomposition effect. This study is the first cross-comparison retrospective study of human decomposition across three different geographical regions. To assess the effect of the most influential taphonomic variables on the decomposition rate (as measured by the Total Decomposition Score (TDS)), decomposition data was examined from the Forensic Anthropology Research Facility at the University of Tennessee (n = 312), the Allegheny County Office of the Medical Examiner in Pittsburgh, US (n = 250), and the Crime Scene Investigation department at Southwest Forensics in the UK (n = 81). Two different BBNs for PMI estimations were created from the US and the UK training data. Sensitivity analysis was performed to identify the most influential parameters of TDS variance, with weaker variables (e.g., age, sex, clothing) being excluded during model refinement. The accuracy of the BBNs was then compared by additional validation cases: US (n = 28) and UK (n = 10). Both models conferred predictive power of the PMI and accounted for the unique combination of taphonomic variables affecting decomposition. Both models had a mean posterior probability of 86% (US) and 81% (UK) in favor of the experimental hypothesis (that the PMI was on, or less than, the prior last known alive date). Neither the US nor the UK datasets represented any cases below 'moderate' support for the value of PMI evidence. By applying coherent probabilistic reasoning to PMI estimations, one logical solution is provided to model the complexities of human decomposition that can quantify the combined effect of several uncertainties surrounding the PMI estimation. This approach communicates the PMI with an associated degree of confidence and provides predictive power on unknown PMI cases.

Not by the Book: Observations of Delayed Oviposition and Re-Colonization of Human Remains by Blow Flies.

Simple SummaryAtypical blow fly colonization is rarely documented in the forensic entomology literature. We demonstrate one case of an exaggerated delay in blow fly colonization and two cases of blow fly re-colonization after cessation of the consumption phase on human remains at the Anthropology Research Facility (University of Tennessee). We recommend interdisciplinary collaboration to better interpret evidence encountered from scenarios comparable to these examples.Postmortem interval estimations can be complicated by the inter-individual variation present in human decomposition. Forensic entomologists may especially face challenges interpreting arthropod evidence in scenarios that are not “by the book”, or that vary in unexpected ways. Therefore, it is important to report instances where blow fly colonization does not align with expected soft tissue decomposition as blow fly larvae are often used to produce a time of colonization (TOC) estimation to infer a minimum PMI. We followed the decomposition and blow fly activity of three human donors at the Anthropology Research Facility (University of Tennessee). Delayed oviposition occurred on one donor 115 d post-placement, whereas two donors experienced blow fly re-colonization after cessation of the consumption phase, one 22 d and one more than 200 d after blow fly larvae were last observed. A null hypothesis model tested whether the entomological TOC and anthropological total body score (TBS) estimations encompassed the time of placement (TOP) for each donor. While the null hypothesis was rejected for all TOC estimations, it could not be rejected for the TBS estimations. We discuss how the non-linear nature of human decomposition can pose challenges to interpreting blow fly evidence and suggest that forensic entomology practitioners should recognize these limitations in both research endeavors and applied casework.

Biodiversity of Forensically Relevant Blowflies (Diptera: Calliphoridae) at the Anthropology Research Facility in Knoxville, Tennessee, USA.

Simple SummaryThis study investigates the biodiversity and seasonal distribution of blowflies at the Anthropology Research Facility (ARF) of the University of Tennessee, which is also known as the “Body Farm”. Blowflies are among the first insects that access dead bodies, and have a significant impact on the rate and pattern of decomposition. Although the ARF has been used for numerous taphonomic and entomological studies over the past 40 years, it is not yet fully known what blowfly species are present in the area. After a 14-month-long blowfly survey at the ARF, we collected a total of 3180 adult blowflies, comprising 13 species from 7 genera. Phormia regina (Meigen) and Lucilia coeruleiviridis (Macquart) were the predominant species collected from this survey, representing 65.9% and 20.6% of collections, respectively. Among the 13 species, Protophormia terraenovae (Robineau-Desvoidy) was collected for the first time in Tennessee. In addition to relative abundance, we also investigated blowfly community composition, species abundance, richness, and diversity by season. This research is expected to provide researchers at the ARF with accurate information about the blowflies so that they can plan and design their research accordingly.Understanding the biodiversity and distribution of forensically relevant blowflies (Diptera: Calliphoridae) in a region can aid in legal investigations when insects are associated with remains. For this purpose, we conducted a 14-month-long blowfly survey at the Anthropology Research Facility (ARF) of the University of Tennessee in Knoxville, Tennessee. Traps baited with pork kidney were deployed for 24 h twice a month throughout the study. A total of 3180 adult blowflies were collected, comprising 13 species from 7 genera. Phormia regina (Meigen) and Lucilia coeruleiviridis (Macquart) were the predominant species collected from this survey, with collections representing 65.9% and 20.6%of total flies captured, respectively. In addition to relative abundance, we investigated blowfly community composition, species abundance, richness, and diversity by season. One state record was identified, with adult Protophormia terraenovae (Robineau-Desvoidy) being collected for the first time in Tennessee. Additionally, an earlier record of Chrysomya megacephala (Fabricius) in Tennessee was noted. These findings can be used to aid in legal investigations in the area and surrounding areas where work is limited, as well as to provide information on which forensically relevant species should be the subject of future research in the area.

Considerations for Stable Isotope Analysis of Human Hair

Stable isotope analysis of postmortem hair is performed in order to make inferences about an individual’s diet and geographic travel history prior to death. During analysis and interpretation, investigators assume that the hair collected from a postmortem environment has not been altered by exposure conditions and that the isotopic “signatures” of hair prior to exposure are preserved in postmortem samples. In order to confidently make inferences from postmortem hair samples, it is necessary to know whether their isotope ratios undergo postmortem changes. To address this question, post-exposure hair samples (n = 44) were collected from known body donors at the Anthropology Research Facility in Knoxville, Tennessee, USA, at various time points ranging from 22 to 1,140 days of exposure. These samples were analyzed for carbon (δ13C), nitrogen (δ15N), hydrogen (δ2H), and oxygen (δ18O) isotope ratios, and the results were compared with pre-exposure hair samples collected from the same donors. This study highlights considerations for the interpretation of isotope ratios obtained from postmortem hair samples in forensic contexts. The results indicate that δ13C, δ15N, and δ18O values from human hair remain relatively consistent over periods up to three years of outdoor exposure, while δ2H values changed significantly between pre-and post-exposure hair samples.

First record of the oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), in Tennessee, USA.

Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) is a medically and forensically important blow fly species that invaded the United States three decades ago and has continued to expand its distribution across the country ever since. Unlike many other blow fly species, larvae of C. megacephala can develop in feces, particularly from humans. Additionally, C. megacephala is known to carry antibiotic-resistant bacteria in even greater quantities than house flies in tropical areas. This behavior, along with its dissemination into and prevalence within human inhabited environments (e.g., outdoor markets, urban neighborhoods), makes C. megacephala a potential threat to human health. This short communication serves as the first record of C. megacephala in Tennessee, USA. Collections of adult and larval blow flies were made from two sets of human remains decomposing at the Anthropology Research Facility (ARF) at the University of Tennessee. Specimens were confirmed by an expert to be C. megacephala. A total of seven individual specimens (four adults and three larvae) of C. megacephala were collected from human bodies at the ARF. These results indicate that C. megacephala is not just dispersing into this environment as adults, but actively colonizing human remains in this semi-urban area. These observations support the previously described behavior and habitat of this filth-breeding fly in many Asian countries where it is considered medically and forensically important. Therefore, continuously updated distribution records, like this one, are critical for tracking the movement of C. megacephala across the United States.

Reprint of: The effects of decomposition and environment on antemortem H-Pb-Sr isotope compositions and degradation of human scalp hair: Actualistic taphonomic observations

Multi-isotope analysis (e.g., Sr-Pb-O-H-C-N) of human scalp hair is routinely used in forensic investigations of human remains to constrain the geographic origin of unidentified bodies, and to investigate antemortem mobility patterns. However, while it is known that postmortem processes can affect the preservation of, or even overprint, the biogenic isotopic signatures in hair, the speed and nature of these processes have rarely been studied. This study investigates the effects of decomposition and environment on the H-Pb-Sr isotope compositions of human hair as well as the relationship between structural hair shaft degradation and isotopic signature change over time. Human scalp hair samples from four body donations were collected at different stages throughout gross body decomposition. The willed-donated bodies were placed to decompose outdoors at the Forensic Anthropology Research Facility (FARF) at Texas State University. Hair fibres from two of the donations were examined using scanning electron microscopy (SEM) and high-resolution light microscopy (HRLM). Chemical and microbiological degradation of hair fibres occurred rapidly after placement of the body outdoors. Measurements of scalp hair isotopic composition demonstrated that H-Pb-Sr isotope ratios were altered within days after environmental exposure, presumably by deposition, leaching and/or exchange with the local bioavailable soil, and vapour. The degree of physical hair degradation and changes in H-Pb-Sr isotope composition were not correlated. We conclude that antemortem isotopic H-Pb-Sr isotope ratios are difficult to recover in hairs derived from decomposing whole bodies.

The effect of seasonality on the application of accumulated degree-days to estimate the early post-mortem interval

This study investigated the effect of seasonal variables on decomposition in the early post-mortem period using 26 donated human cadavers at the University of Tennessee’s Anthropology Research Facility (ARF), USA. The rate and pattern of decomposition in human cadavers (as measured by TBS and the revised TBSsurf methods) did not vary significantly between all seasons. Summer and autumn cadavers had comparable rates of accelerated decomposition despite significant differences in both ADD and temperature (p<0.05). Spring cadavers had the slowest onset of decomposition characteristics, even compared to the few decomposition characteristics expressed in winter. Seasonal variation in humidity, rather than temperature, may be the overarching driving force for decomposition progression in the early post-mortem period. Both TBS and TBSsurf methods were poor predictors of the PMI (R2=0.4) and significantly over-estimated the PMI across all seasons, although to a lesser extent in spring. This study also demonstrated no relationship between known ADD and TBS/TBSsurf (R2=0.025). TBS and TBSsurf are ADD-based PMI estimation models that cannot be validated under experimental conditions. Accounting for seasonal expression of individual decomposition characteristics is needed for improvement of PMI predictability in forensic practice.

Phase II spatial patterning of vulture scavenged human remains

This project expands on a pilot study by Spradley, Hamilton, and Giordano (2012) that investigated the patterns and effect of vulture scavenging of human remains, with special focus on the effect of microenvironments. Five donated bodies from the Willed Body Donation Program at Texas State University were placed in various locations at the university’s Forensic Anthropology Research Facility (FARF). The bodies were monitored by motion capture cameras and after each vulture scavenging event the dispersal and location of the bodies’ skeletal elements were mapped with a high accuracy GPS unit. The degree and direction of dispersal by vultures were then analyzed with GIS.Phase II revealed that vultures will begin scavenging at variable times, will continue to return to and move remains after a body has been skeletonized, and tend to move remains from higher elevations to lower elevations. The data also suggested that vultures may scavenge in larger groups (n > 20) in cooler temperatures, but in warm to hot temperatures they may scavenge more frequently in smaller groups (n ≈ 5). Future directions for vulture scavenging profiles are briefly discussed.

The effects of decomposition and environment on antemortem H-Pb-Sr isotope compositions and degradation of human scalp hair: Actualistic taphonomic observations

Multi-isotope analysis (e.g., Sr–Pb–O–H–C–N) of human scalp hair is routinely used in forensic investigations of human remains to constrain the geographic origin of unidentified bodies, and to investigate antemortem mobility patterns. However, while it is known that postmortem processes can affect the preservation of, or even overprint, the biogenic isotopic signatures in hair, the speed and nature of these processes have rarely been studied. This study investigates the effects of decomposition and environment on the H–Pb–Sr isotope compositions of human hair as well as the relationship between structural hair shaft degradation and isotopic signature change over time. Human scalp hair samples from four body donations were collected at different stages throughout gross body decomposition. The willed-donated bodies were placed to decompose outdoors at the Forensic Anthropology Research Facility (FARF) at Texas State University. Hair fibers from two of the donations were examined using scanning electron microscopy (SEM) and high-resolution light microscopy (HRLM). Chemical and microbiological degradation of hair fibers occurred rapidly after placement of the body outdoors. Measurements of scalp hair isotopic composition demonstrated that H–Pb–Sr isotope ratios were altered within days after environmental exposure, presumably by deposition, leaching and/or exchange with the local bioavailable soil, and vapor. The degree of physical hair degradation and changes in H–Pb–Sr isotope composition were not correlated. We conclude that antemortem isotopic H–Pb–Sr isotope ratios are difficult to recover in hairs derived from decomposing whole bodies.

Moisture Content in Decomposing, Desiccated, and Mummified Human Tissue

Due to the nature of mummification, tissue that has been significantly desiccated may never reach the advanced stages of decomposition. This research measured the moisture content of five donated individuals placed at the Forensic Anthropology Research Facility at Texas State University over a period of nearly three months. Moisture-content readings were taken from 20 sites on each body on a daily basis and then analyzed through multilevel modeling with temperature, humidity, solar radiation, and precipitation. This study found that desiccation appears to follow a consistent, asymptotic pattern and that temperature is the most influential environmental factor affecting moisture content. This study shows the viability for a postmortem interval estimation method based on accumulated degree-days and moisture content.

Survey and Insights into Unmanned Aerial-Vehicle-Based Detection and Documentation of Clandestine Graves and Human Remains

Numerous biological and archaeological studies have demonstrated the legitimacy of remote sensing in anthropology. This article focuses on detecting and documenting terrestrial clandestine graves and surface remains (CGSR) of humans using unmanned aerial vehicles (UAVs), sensors, and automatic processing algorithms. CGSR is a problem of complex decision making under uncertainty that requires the identifijication and intelligent reasoning about direct evidence of human remains and their environmental fijingerprints. As such, it is as much an engineering and geospatial problem as it is an anthropology problem. This article is an efffort to survey existing work across disciplines and to provide insights and recommendations to assist future research. To support our claims, preliminary experiments were performed at the Forensic Anthropological Research Facility at Texas State University using UAVs, hyperspectral imaging, thermal imaging, and structure from motion. Prior work, our experience, and preliminary results indicate that both great potential and extreme challenges face remote sensing of CGSR.

Impact of sample degradation and inhibition on field-based DNA identification of human remains

The advent of DNA technologies for field-based application promises to provide rapid intelligence to aid investigations. Their validation and adoption by enforcement groups have demonstrated utility in sample screening and prioritisation, but field application in some areas of forensic science, such as human remains identification, is little evidenced. Assessing the ability of such approaches to provide meaningful data is critical as decomposition is likely to complicate analysis and limit the effective use of such field-based DNA interventions. This research assessed the ability to collect viable DNA data in the field using the ParaDNA Field Instrument and Intelligence Test chemistry. Different sample collection methods were assessed; direct from skin surface; direct from exposed tissue; indirect from muscle swab transferred to FTA card; and from larvae on the donors. Samples were collected and processed on-site at the Anthropology Research Facility, University of Tennessee. The data show that the muscle tissue provided the most effective sample template and, using this approach, it was possible to generate STR profiles from human remains in under two hours from the time of sample collection. STR profile data were collected up to four days from donor placement (114 Accumulated Degree Days). After this time there was a rapid decrease in the quality of the profiles collected due to the onset of decomposition. The data also show that effective sample recovery was not possible from the surface of the skin, exposed tissue or from carrion larvae. Inhibition studies in the laboratory suggest that by-products of the decomposition process are the primary mode of failure. Together these data suggests a possible application for screening and prioritisation in criminal casework but highlights issues that may affect the success of the approach.

Survey and Insights into Unmanned Aerial-Vehicle-Based Detection and Documentation of Clandestine Graves and Human Remains

Numerous biological and archaeological studies have demonstrated the legitimacy of remote sensing in anthropology. This article focuses on detecting and documenting terrestrial clandestine graves and surface remains (CGSR) of humans using unmanned aerial vehicles (UAVs), sensors, and automatic processing algorithms. CGSR is a problem of complex decision making under uncertainty that requires the identification and intelligent reasoning about direct evidence of human remains and their environmental fingerprints. As such, it is as much an engineering and geospatial problem as it is an anthropology problem. This article is an effort to survey existing work across disciplines and to provide insights and recommendations to assist future research. To support our claims, preliminary experiments were performed at the Forensic Anthropological Research Facility at Texas State University using UAVs, hyperspectral imaging, thermal imaging, and structure from motion. Prior work, our experience, and preliminary results indicate that both great potential and extreme challenges face remote sensing of CGSR.

An evaluation of soil chemistry in human cadaver decomposition islands: Potential for estimating postmortem interval (PMI)

Soil samples from the Forensic Anthropology Research Facility (FARF) at Texas State University, San Marcos, TX, were analyzed for multiple soil characteristics from cadaver decomposition islands to a depth of 5centimeters (cm) from 63 human decomposition sites, as well as depths up to 15cm in a subset of 11 of the cadaver decomposition islands plus control soils. Postmortem interval (PMI) of the cadaver decomposition islands ranged from 6 to 1752 days. Some soil chemistry, including nitrate-N (NO3-N), ammonium-N (NH4-N), and dissolved inorganic carbon (DIC), peaked at early PMI values and their concentrations at 0–5cm returned to near control values over time likely due to translocation down the soil profile. Other soil chemistry, including dissolved organic carbon (DOC), dissolved organic nitrogen (DON), orthophosphate-P (PO4-P), sodium (Na+), and potassium (K+), remained higher than the control soil up to a PMI of 1752days postmortem. The body mass index (BMI) of the cadaver appeared to have some effect on the cadaver decomposition island chemistry. To estimate PMI using soil chemistry, backward, stepwise multiple regression analysis was used with PMI as the dependent variable and soil chemistry, body mass index (BMI) and physical soil characteristics such as saturated hydraulic conductivity as independent variables. Measures of soil parameters derived from predator and microbial mediated decomposition of human remains shows promise in estimating PMI to within 365days for a period up to nearly five years. This persistent change in soil chemistry extends the ability to estimate PMI beyond the traditionally utilized methods of entomology and taphonomy in support of medical-legal investigations, humanitarian recovery efforts, and criminal and civil cases.