Archaeological theories and methods are developed to reconstruct past human behavior from fragmentary material remains. The interrelated discipline of physical anthropology addresses questions related to skeletal remains while acknowledging taphonomic parameters. The benefit of integrating these disciplines in forensic investigations has gained increasing acknowledgement over the last decades, but the use of forensic archaeology and anthropology (FAA) remains limited in Sweden. The aim of this study is to analyze the field of FAA in Sweden in relation to outdoor and fire crime scenes where human remains are encountered. Based on qualitative interviews, the state and potential developments of FAA within the Swedish police and the National Board of Forensic Medicine are discussed. The results show that for ensic investigations and analysis of human fragmentary remains are not standardized in Sweden. A great responsibility is placed on the individual crime scene investigator who elects how to investigate these sites and who to contract for the analysis of osteological remains. This can endanger evidence collection and interpretation. This study shows that investigations of buried or fragmentary human remains in Sweden could be aided by a development of FAA. Key steps to further development of FAA within Swedish police involve 1) quantifying cases that could benefit from FAA, 2) establish FAA as an independent subject, 3) develop a national infrastructure, 4) offer professional education in the subject(s), and 4) develop best practice to advance evidence collection and legal security in investigations involving fragmentary human remains. An ongoing ISO accreditation of outdoor crime scene investigations within the Swedish police will hopefully benefit FAA development and collaborations with external partners.

This paper presents a quantitative retrospective study of gross human decomposition in central and southeastern Sweden. The applicability of methods developed abroad for postmortem interval (PMI) estimation from decomposition morphology and temperature are is evaluated. Ninety‐four cases were analyzed (43 terrestrial and 51 aquatic) with a median PMI of 48 days. The results revealed differences in decomposition patterns between aquatic, surface, hanging, and buried remains. While partial saponification and desiccation occurred in cases of surface remains, complete skeletonization was observed in all cases with a PMI over two years. Aquatic skeletonization was slower due to extensive saponification in cases with PMI higher than one year. Formulae for assessing accumulated degree‐days (ADD) from the original methods did not fit the study material. However, a regression analysis demonstrated that 80% of decomposition variance in surface remains could be explained by ADD, suggesting that a geographically adapted equation holds promise for assessing PMI. In contrast, the model fit was poor for aquatic cases (43%). While this may be explained by problems in obtaining reliant aquatic temperature data or an insufficient scoring system, aquatic decomposition may be highly dependent on factors other than ADD alone. This study evaluates the applicability of current PMI methods on an outdoor sample from a previously unpublished region, and represents the first scientific publication of human outdoor decomposition patterns in Sweden. Suggestions for future research are provided, including that scoring methods should incorporate saponification to fit forensic taphonomy in Swedish environments.

In this study, we present an experiment design and assess the capability of multiple geophysical techniques to image buried human remains in mass and individual graves using human cadavers willingly donated for scientific research. The study is part of a novel, interdisciplinary mass grave experiment established in May 2021 which consists of a mass grave with 6 human remains, 3 individual graves and two empty control graves dug to the same size as the mass grave and individual graves. Prior to establishing the graves, we conducted background measurements of electrical resistivity tomography (ERT), electromagnetics (EM), and ground penetrating radar (GPR) while soil profiles were analyzed in situ after excavating the graves. All graves were also instrumented with soil sensors for monitoring temporal changes in soil moisture, temperature, and electrical conductivity in situ. Measurements of ERT, EM and GPR were repeated 3, 37, 71 and 185 days after burial with further repeated measurements planned for another twelve months. ERT results show an initial increase in resistivity in all graves including the control graves at 3 days after burial and a continuous decrease thereafter in the mass and individual graves with the strongest decrease in the mass grave. Conductivity distribution from the EM shows a similar trend to the ERT with an initial decrease in the first 3 days after burial. Distortion in linear reflectors, presence of small hyperbolas and isolated strong amplitude reflectors in the GPR profiles across the graves is associated with known locations of the graves. These initial results validate the capability of geoelectrical methods in detecting anomalies associated with disturbed ground and human decay while GPR though show some success is limited by the geology of the site.

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.

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.

Bone proteomic studies using animal proxies and skeletonized human remains have delivered encouraging results in the search for potential biomarkers for precise and accurate postmortem interval (PMI) and the age-at-death (AAD) estimation in medico-legal investigations. The development of forensic proteomics for PMI and AAD estimation is in critical need of research on human remains throughout decomposition, as currently the effects of both inter-individual biological differences and taphonomic alteration on the survival of human bone protein profiles are unclear. This study investigated the human bone proteome in four human body donors studied throughout decomposition outdoors. The effects of ageing phenomena (in vivo and post-mortem) and intrinsic and extrinsic variables on the variety and abundancy of the bone proteome were assessed. Results indicate that taphonomic and biological variables play a significant role in the survival of proteins in bone. Our findings suggest that inter-individual and inter-skeletal differences in bone mineral density (BMD) are important variables affecting the survival of proteins. Specific proteins survive better within the mineral matrix due to their mineral-binding properties. The mineral matrix likely also protects these proteins by restricting the movement of decomposer microbes. New potential biomarkers for PMI estimation and AAD estimation were identified. Future development of forensic bone proteomics should include standard measurement of BMD and target a combination of different biomarkers.

Human DNA samples can remain unaltered for years and preserve important genetic information for forensic investigations. In fact, besides human genetic information, these extracts potentially contain additional valuable information: microbiome signatures. Forensic microbiology is rapidly becoming a significant tool for estimating post-mortem interval (PMI), and establishing cause of death and personal identity. To date, the possibility to recover unaltered microbiome signatures from human DNA extracts has not been proven. This study examines the microbiome signatures within human DNA extracts obtained from six cadavers with different PMIs, which were stored frozen for 5–16 years. Results demonstrated that the microbiome can be co-extracted with human DNA using forensic kits designed to extract the human host’s DNA from different tissues and fluids during decomposition. We compared the microbial communities identified in these samples with microbial DNA recovered from two human cadavers donated to the Forensic Anthropology Center at Texas State University (FACTS) during multiple decomposition stages, to examine whether the microbial signatures recovered from “old” (up to 16 years) extracts are consistent with those identified in recently extracted microbial DNA samples. The V4 region of 16 S rRNA gene was amplified and sequenced using Illumina MiSeq for all DNA extracts. The results obtained from the human DNA extracts were compared with each other and with the microbial DNA from the FACTS samples. Overall, we found that the presence of specific microbial taxa depends on the decomposition stage, the type of tissue, and the depositional environment. We found no indications of contamination in the microbial signatures, or any alterations attributable to the long-term frozen storage of the extracts, demonstrating that older human DNA extracts are a reliable source of such microbial signatures. No shared Core Microbiome (CM) was identified amongst the total 18 samples, but we identified certain species in association with the different decomposition stages, offering potential for the use of microbial signatures co-extracted with human DNA samples for PMI estimation in future. Unveiling the new significance of older human DNA extracts brings with it important ethical-legal considerations. Currently, there are no shared legal frameworks governing the long-term storage and use of human DNA extracts obtained from crime scene evidence for additional research purposes. It is therefore important to create common protocols on the storage of biological material collected at crime scenes. We review existing legislation and guidelines, and identify some important limitations for the further development and application of forensic microbiomics.