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Death is a universal phenomenon and what happens after life has led to extensive forensic ecology research. Consequently, we now know that the shell of the once living provides fertile ground for other life forms, spanning prokaryotic microbes to large, vertebrate scavengers. This ephemeral patch of newly available resources also provides rich sources of evidence that can be used in death investigation. In recent years there have been substantial advances in technology that have facilitated the research and application of human remains decomposition in ways that harness theory and basic understanding of the ecological and evolutionary sciences (Tomberlin et al., 2011). To that end, this special issue covers the most recent perspectives and research that explores the complex ways that the once living can provide important information to the forensic sciences, in ways that can ultimately be applied to the judicial system and its processes. It is within this context of linking basic research in death and decomposition to applications of forensics that the special topic was born. 

In this century, drug abuse continues to be a national crisis. Since 1999, the number of opioid-induced overdoses has increased four-fold to more than 500,000 deaths. The microbiota gut-brain-axis is a bidirectional circuit that links the neural, endocrine, and immunological systems with gut microbial communities. Gut microbiota play significant roles in human mind and behavior, specifically pain perception, learning capacity and memory, mood, and emotion, and anxiolytic effects and temperament. Also, disruptions in the gut microbiome have been associated with substance use disorders. While much research still needs to be performed, elucidating the interplay of gut microbiota in substance abuse disorders may produce promising avenues for future forensic development. The goal of the current study was to determine gut microbiome composition in substance abuse disorder cases using transverse colon tissues of 21 overdose criminal cases versus 19 non-overdose-related cases. The hypothesis was that postmortem samples of the same origin will reveal similar taxonomic relationships. Using weighted UniFrac analysis, drug abuse was found to be a significant factor in determining microbiome similarity (F = 1.93; df = 1, 35; p < 0.048; R2 = 0.05) indicating that there are detectable differences in composition that are attributable to substance abuse. Using unweighted UniFrac, however, sex was instead found to be a significant predictor of microbiome similarity (F = 1.88; df = 1, 30; p = 0.028; R2 = 0.05). A heatmap was generated of the relative abundances of the 30 most prevalent bacteria per case and their associated substance profile. The results revealed that samples of the same origin cluster together, showing a high degree of similarity between samples and a low degree of similarity among samples of different origin. This examination of human transverse colon microflora in decomposing cadavers expands the emerging literature on postmortem microbial communities, which will ultimately contribute to advanced knowledge of putrefaction. 

Italy and the United States are two of the countries most affected by SARS-CoV-2 (COVID-19), with more than 240,760 confirmed cases in Italy and 2,699,658 in the United States (as of July 2, 2020). The current COVID-19 pandemic has led to substantial changes in many fields of medicine, specifically in the forensic discipline. Medicolegal activities related to conducting autopsies have been largely affected by the COVID-19 pandemic. Postmortem examinations are generally discouraged by government regulations due to the risk of spreading the disease further through the handling and dissection of bodies from patients who succumbed to COVID-19 infection. There is a paucity of data regarding the persistence of SARS-CoV-2 in bodies, as well as concerning the reliability of swabbing methods in human remains. On the other hand, the autopsy is an essential tool to provide necessary information about the pathophysiology of the disease that presents useful clinical and epidemiological insights. On this basis, we aim to address issues concerning general medical examiner/coroner organization, comparing the Italian and American systems. We also discuss the pivotal roles of forensic pathologists in informing infectious disease surveillance. Finally, we focus on the impact of COVID-19 emergency on medicolegal practices in Italy and the United States, as well as the responses of the forensic scientific community to the emerging concerns related to the pandemic. We believe that stronger efforts by authorities are necessary to facilitate completing postmortem examinations, as data derived from such assessments are expected to be paramount to improving patient management and disease prevention. 

Human thanatomicrobiota studies have shown that microorganisms inhabit and proliferate externally and internally throughout the body and are the primary mediators of putrefaction after death. Yet little is known about the source and diversity of the thanatomicrobiome or the underlying factors leading to delayed decomposition exhibited by reproductive organs. The use of the V4 hypervariable region of bacterial 16S rRNA gene sequences for taxonomic classification (“barcoding”) and phylogenetic analyses of human postmortem microbiota has recently emerged as a possible tool in forensic microbiology. The goal of this study was to apply a 16S rRNA barcoding approach to investigate variation among different organs, as well as the extent to which microbial associations among different body organs in human cadavers can be used to predict forensically important determinations, such as cause and time of death. We assessed microbiota of organ tissues including brain, heart, liver, spleen, prostate, and uterus collected at autopsy from criminal casework of 40 Italian cadavers with times of death ranging from 24 to 432 h. Both the uterus and prostate had a significantly higher alpha diversity compared to other anatomical sites, and exhibited a significantly different microbial community composition from non-reproductive organs, which we found to be dominated by the bacterial orders MLE1-12, Saprospirales, and Burkholderiales. In contrast, reproductive organs were dominated by Clostridiales, Lactobacillales, and showed a marked decrease in relative abundance of MLE1-12. These results provide insight into the observation that the uterus and prostate are the last internal organs to decay during human decomposition. We conclude that distinct community profiles of reproductive versus non-reproductive organs may help guide the application of forensic microbiology tools to investigations of human cadavers.