Postmortem Submersion Interval Research Articles

A fundamental study on postmortem submersion interval estimation by metabolomics analyzing of gastrocnemius muscle from submersed rat models in freshwater.

In forensic practice, determining the postmortem submersion interval (PMSI) and cause-of-death of cadavers in aquatic ecosystems has always been challenging task. Traditional approaches are not yet able to address these issues effectively and adequately. Our previous study proposed novel models to predict the PMSI and cause-of-death based on metabolites of blood from rats immersed in freshwater. However, with the advance of putrefaction, it is hardly to obtain blood samples beyond 3 days postmortem. To further assess the feasibility of PMSI estimation and drowning diagnosis in the later postmortem phase, gastrocnemius, the more degradation-resistant tissue, was collected from drowned rats and postmortem submersion model in freshwater immediately after death, and at 1day, 3 days, 5 days, 7 days, and 10 days postmortem respectively. Then the samples were analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate the dynamic changes of the metabolites. A total of 924 metabolites were identified. Similar chronological changes of gastrocnemius metabolites were observed in the drowning and postmortem submersion groups. The difference in metabolic profiles between drowning and postmortem submersion groups was only evident in the initial 1day postmortem, which was faded as the PMSI extension. Nineteen metabolites representing temporally-dynamic patterns were selected as biomarkers for PMSI estimation. A regression model was built based on these biomarkers with random forest algorithm, which yielded a mean absolute error (± SE) of 5.856 (± 1.296) h on validation samples from an independent experiment. These findings added to our knowledge of chronological changes in muscle metabolites from submerged vertebrate remains during decomposition, which provided a new perspective for PMSI estimation.

Marine bryozoan colonization of terrestrial biomineralized tissues: Taphonomic insights and forensic implications

AbstractThe taphonomy and diagenesis of bone and teeth recovered from any environments provide crucial information for forensic sciences and investigations. This leads to the estimation of the postmortem interval (PMI) and the postmortem submersion interval (PMSI) of the organism/s. Aquatic taxa can induce macroscopic and microscopic alterations in biomineralized tissues (e.g., grooves) or can colonize them by attachment (e.g., Bryozoa). Bryozoa are tiny invertebrates that form colonies in freshwater and saltwater. They can survive for years as suspension feeders in all climates. Most marine Bryozoa species have a biomineralized exoskeleton that can be preserved after their death. This research analyzes eight fragments of archeological elephant ivory with a known PMSI of 314 years, which were inhabited by three distinct bryozoan colonies. The variations in the preservation of the bryozoan exoskeletons and the overgrowth of different marine taxa reveal that one colony (lichenoporid cyclostomatid) was alive at the time of the ivory collection from the submerged archeological site while the two other colonies (cheilostomatid) had previously died at different times. The primary objective of this observation is to contribute to the understanding of the taphonomy of terrestrial mammalian biomineralized tissues recovered in marine environments. Additionally, the study discusses the potential forensic implications of this association, such as the evidence of marine submersion and the PMSI. A secondary objective is to present the Bryozoa colonies within a distinctive depositional context, considering that many bryozoan species of the Western Australian coast remain undescribed. The complexity of the Bryozoa ecobiology is also highlighted, with the need of further research (e.g., minimum time for colonization). Finally, this study highlights the urgency of multidisciplinary collaboration to advance aquatic forensic capabilities.

The degradation of collagen in submerged bones, analysed by ImageJ® and Orbit®, for the estimation of the post-mortem interval (PMI) and the post-mortem submersion interval (PMSI)

ABSTRACT The estimation of the post-mortem submersion interval (PMSI) of skeletal remains can provide critical information to forensic investigations, contributing to various aspects such as identification. A fundamental aspect of the PMSI estimation in bone is the degradation of collagen, the most abundant organic component. This degradation can be assessed using various analytical techniques, including the digital analysis of images taken from histological slides. Two open-source software for image digital analysis, ImageJ® and Orbit®, provide novice-friendly and accessible technology to a broad audience of forensic practitioners. However, the absence of established procedures can challenge the consistency of the interpretation of the results, especially between observers. The principal aim of this study was to compare the efficacy of ImageJ® and Orbit® in quantifying the degradation of collagen in images taken from histological slides of mammalian non-human bones submerged for 4 months to 2 years. Despite the inconsistency in the outcomes of intraobserver vs. interobserver testing, this research has demonstrated the promising potential of digital histology. It has also identified the need for further investigation, particularly focusing on the usability of ImageJ® and the refinement of the Orbit® workflow.

Multidisciplinary analyses of partial human remains discovered in the Caribbean Sea (Venezuela)

ABSTRACT In March 2022, human remains were discovered submerged 15 metres underwater, near Cubagua Island, Venezuela. The remains were intricately entangled and secured to the seafloor. The investigation was conducted by the Servicio Nacional de Medicina y Ciencias Forenses (SENAMECF) of Venezuela, and it involved an underwater recovery operation, followed by a comprehensive examination. The medicolegal, anthropological, odontological, and taphonomical analyses alongside diatom test were conducted to ascertain the identity of the remains, determine the cause of death, and estimate the post-mortem interval (PMI)/post-mortem submersion interval (PMSI). Collaborative efforts with international experts on adipocere and barnacle analyses allowed for the refinement of the enhanced the precision of information provided in plea announcements, which facilitated the identification of the subject. Forensic analyses on incomplete and highly decomposed human remains present inherent complexities, which are exacerbated in underwater environments. Compounded by the limited experience and expertise in aquatic forensics among law enforcement agencies worldwide, the present case exemplifies a successful professional collaboration that surmounted a diverse array of challenges. This case underscores the critical importance of knowledge-sharing within the continuously evolving field of forensic science, serves as an illustrative example, and provides guidelines for the investigation of similar cases in the future.

Cadaver transport in large river systems: winter case study in the South Saskatchewan River

An average of 518 drownings occur in Canada per year but few studies measured post-mortem submersion for cadavers and those studies are limited to warm areas of Europe and US. In our current study we deployed a pig cadaver in the South Saskatchewan River system in winter to monitor distance traveled and timing under ice conditions using radio-telemetry. We monitored accumulated degree days before bloating in the cadaver to estimate timing of emersion in winter drowning victims. Post-mortem submersion interval of the cadaver was relatively long (∼94 days) with an accumulated degree day estimate of ∼ 311 °C, and ultimately ∼189.9 km travelled. Our results suggest that winter drowning victims may remain at their point of disappearance for a substantial longer time compared to warmer regions; thereby providing adequate searching time to locate bodies shortly after disappearance.

Decomposition in an artificial lentic environment: approaches to post-mortem interval estimation

ABSTRACT While terrestrial decomposition has been extensively researched to produce reliable methods of estimating the post-mortem interval of remains, there is limited literature documenting aquatic decomposition. Consequently, the ability to reliably estimate the post-mortem submersion interval for remains in water bodies is poor, despite markedly varying insect succession between aquatic and terrestrial decomposition This study was conducted to compare decomposition on Sus domesticus carcases in terrestrial and artificial lentic environments, aiming to provide more detailed characterization of aquatic decomposition and document the role of terrestrial organisms in the accompanying insect succession. Three trials consisting of six stillborn piglets in lentic environments and three in terrestrial environments were observed daily over a period of 12 months. Decomposition stage and morphological changes between terrestrial and lentic piglets were noted. Insects were sampled from remains and reared to adulthood for identification. Lentic decomposition was prolonged relative to terrestrial decomposition, reflecting aquatic decomposition characteristics accompanied by terrestrial insect colonization. Diptera were more prevalent on terrestrial remains, and Coleoptera in the lentic environments, with few dipteran taxa common between environments. Results show the variability of decomposition stages, characteristics and insects between terrestrial and lentic remains, and are discussed with regard to implications for aquatic forensic casework.

Assessment of post‐mortem submersion interval using total aquatic decomposition scores of drowned human cadavers

Investigating drowning-related deaths remains a significant problem for forensic personnel all over the world. The previously published decomposition scoring method like the total aquatic decomposition (TAD) score promises to estimate the correct post-mortem submersion interval (PMSI) in aquatic habitats through the assessment and calculation of the decomposition rate and accumulated degree days (ADD). The current study comprised of 53 drowned death cases belonging to various districts of Haryana from May 2016 to August 2017. The regression and Pearson's correlation indicated a significant correlation between the TAD scores and the actual ADD (calculated through water temperatures) (r2 =0.917) and between the actual and the estimated ADDs (calculated through TAD scores used by Heaton et al. [21]) (r=0.9585). The results indicated that the estimated ADD tends to over predict the PMSI compared to the actual ADD. It is further confirmed by paired t-test, which showed the mean of actual ADD (mean=349) to be significantly lower than the mean of estimated ADD (mean=663). Moreover, these methods will help forensic investigators and researchers formulate region-specific regression equations for PMSI estimation.

Postmortem submersion intervals in the River Thames

This paper catalogues a dataset drawn from Metropolitan Police records in the period 2004-2015 regarding drowning victims recovered from a tidal stretch of the River Thames and provides a comparative study with a similar dataset from the time period 1956-1959 by the County of London (Western District), H.M. Coroner of that time, Gavin Thurston, from the information gathered in his professional role. In addition to drawing comparisons between these time periods the paper draws inferences regarding the Post-Mortem Submersion Interval (PMSI) and proposing further study required. Both datasets show a significant bias towards male subjects counter to other comparable data in the literature. This bias is even more pronounced in the 2004-2015 period where additionally there are significantly more incidents during Full Moon Lunar Phase. Some weak seasonal trends were observed regarding equinoctial peaks but these were not statistically significant. There are few clear trends observable in factors that might influence Post-Mortem Submersion Interval although there was a weak and counter-intuitive inverse relationship between clothing weight and time in water. KEY WORDS: PMSI, Drowning, GIS

Marine sponge bioerosion in the forensic taphonomy of terrestrial bone

Bone and teeth, specialised bio-mineralized connective tissues, are left after the typical decomposition process of any vertebrate organism. Their analysis can reveal insights into an organism's life and retrace the history of the remains after death (also known as taphonomy), which ultimately evolves to destruction or fossilization. Studies on the taphonomy of terrestrial mammalian bio-mineralized tissues have mostly focussed on terrestrial depositional environments. Here, samples submerged in the marine environment are investigated.Five archaeological bones of terrestrial mammalian species (pig and oxen) with historically known post-mortem submersion interval (PMSI) (69–316 years) and recovery sites, were analysed macroscopically, microscopically and by microCT. The aim was to characterize for the first time the alterations produced by marine bioeroding sponges, and to discuss their potential interdisciplinary application, with special focus on forensic investigations.The pig samples showed microanatomical preservation (Oxford Histological Index = 3–5), increased total porosity, the presence of old tissue flakes with sponge spicules and traces of bioerosion, such as papillary holes, canals and chambers with microsculptured walls. The presence of such tissue flakes suggested that, at the time of recovery, they may have been free of sediment and inhabited by live sponges. The shape of one internal chamber was identified as the ichnospecies Entobia convoluta as typically produced by shallow, warm-water Cliothosa spp. Surface analyses for further biological evidence remained inconclusive.The taphonomy of skeletal remains has always been relevant in anthropological, natural and forensic studies. In forensics, the role of taphonomy is to contribute to personal identification, cause of death and post-mortem interval (PMI). This study detected the past colonization of terrestrial mammalian bone by marine bioeroding sponges, and aimed to link the taphonomic findings to natural processes and environments. Bioeroding sponges are for the first time confirmed to colonize terrestrial mammalian bone submerged in marine environments, and to promote diagenesis through bioerosion.

Association of decomposition in the hands and feet with postmortem submersion interval in the sea

This article aims to evaluate estimation of the postmortem submersion interval (PMSI) for cadavers recovered from the Pacific Ocean in the South Kanto area of Japan. Data were collected from crime scene reports in the 3rd Regional Coast Guard Headquarters over a 11-year period. Approximate time of PMSI was available for 72 cases with the decomposition stage from photo pictures at the scene. No visible changes in the skin of the hands and feet counted from 27 cases, wrinkling and discoloration in 28 cases, and degloving in 17 cases. The average (±S.D.) of accumulated degree days (ADD) was 2.0±3.3, 24.5±19.1, 164.0±112.5, respectively. As minimum ADD, wrinkling and degloving were expected to be formed in 9.4 and 77.8, respectively, which corresponded to a half day and four days at 20°C of sea water temperature. In comparison with other findings, degloving was accompanied by bloated abdomen, sloughing of hairs, and peeling of nails. The characteristic changes of the hands and feet were helpful to estimate PMSI for submerged cadavers. We expect to apply this finding to criminal investigation at the scene.

Postmortem submersion interval estimation of cadavers recovered from freshwater based on gut microbial community succession.

Microbial community succession during decomposition has been proven to be a useful tool for postmortem interval (PMI) estimation. Numerous studies have shown that the intestinal microbial community presented chronological changes after death and was stable in terrestrial corpses with different causes of death. However, the postmortem pattern of intestinal microbial community succession in cadavers retrieved from water remains unclear. For immersed corpses, the postmortem submersion interval (PMSI) is a useful indicator of PMI. To provide reliable estimates of PMSI in forensic investigations, we investigated the gut microbial community succession of corpses submersed in freshwater and explored its potential application in forensic investigation. In this study, the intestinal microbial community of mouse submersed in freshwater that died of drowning or CO2 asphyxia (i.e., postmortem submersion) were characterized by 16S rDNA amplification and high-throughput sequencing, followed by bioinformatic analyses. The results demonstrated that the chronological changes in intestinal bacterial communities were not different between the drowning and postmortem submersion groups. α-diversity decreased significantly within 14 days of decomposition in both groups, and the β-diversity bacterial community structure ordinated chronologically, inferring the functional pathway and phenotype. To estimate PMSI, a regression model was established by random forest (RF) algorithm based on the succession of postmortem microbiota. Furthermore, 15 genera, including Proteus, Enterococcus, and others, were selected as candidate biomarkers to set up a concise predicted model, which provided a prediction of PMSI [MAE (± SE) = 0.818 (± 0.165) d]. Overall, our present study provides evidence that intestinal microbial community succession would be a valuable marker to estimate the PMSI of corpses submerged in an aquatic habitat.

Microbial communities in the liver and brain are informative for postmortem submersion interval estimation in the late phase of decomposition: A study in mouse cadavers recovered from freshwater.

Bodies recovered from water, especially in the late phase of decomposition, pose difficulties to the investigating authorities. Various methods have been proposed for postmortem submersion interval (PMSI) estimation and drowning identification, but some limitations remain. Many recent studies have proved the value of microbiota succession in viscera for postmortem interval estimation. Nevertheless, the visceral microbiota succession and its application for PMSI estimation and drowning identification require further investigation. In the current study, mouse drowning and CO2 asphyxia models were developed, and cadavers were immersed in freshwater for 0 to 14 days. Microbial communities in the liver and brain were characterized via 16S rDNA high-throughput sequencing. Only livers and brains collected from 5 to 14 days postmortem were qualified for sequencing. There was significant variation between microbiota from liver and brain. Differences in microbiota between the cadavers of mice that had drowned and those only subjected to postmortem submersion decreased over the PMSI. Significant successions in microbial communities were observed among the different subgroups within the late phase of the PMSI in livers and brains. Eighteen taxa in the liver which were mainly related to Clostridium_sensu_stricto and Aeromonas, and 26 taxa in the brain which were mainly belonged to Clostridium_sensu_stricto, Acetobacteroides, and Limnochorda, were selected as potential biomarkers for PMSI estimation based on a random forest algorithm. The PMSI estimation models established yielded accurate prediction results with mean absolute errors ± the standard error of 1.282 ± 0.189 d for the liver and 0.989 ± 0.237 d for the brain. The present study provides novel information on visceral postmortem microbiota succession in corpses submerged in freshwater which sheds new light on PMSI estimation based on the liver and brain in forensic practice.

Bacterial Succession in Microbial Biofilm as a Potential Indicator for Postmortem Submersion Interval Estimation.

Bacteria acts as the main decomposer during the process of biodegradation by microbial communities in the ecosystem. Numerous studies have revealed the bacterial succession patterns during carcass decomposition in the terrestrial setting. The machine learning algorithm-generated models based on such temporal succession patterns have been developed for the postmortem interval (PMI) estimation. However, the bacterial succession that occurs on decomposing carcasses in the aquatic environment is poorly understood. In the forensic practice, the postmortem submersion interval (PMSI), which approximately equals to the PMI in most of the common drowning cases, has long been problematic to determine. In the present study, bacterial successions in the epinecrotic biofilm samples collected from the decomposing swine cadavers submerged in water were analyzed by sequencing the variable region 4 (V4) of 16S rDNA. The succession patterns between the repeated experimental settings were repeatable. Using the machine learning algorithm for establishing random forest (RF) models, the microbial community succession patterns in the epinecrotic biofilm samples taken during the 56-day winter trial and 21-day summer trial were determined to be used as the PMSI predictors with the mean absolute error (MAE) of 17.87 ± 2.48 ADD (≈1.3 day) and 20.59 ± 4.89 ADD (≈0.7 day), respectively. Significant differences were observed between the seasons and between the substrates. The data presented in this research suggested that the influences of the environmental factors and the aquatic bacterioplankton on succession patterns of the biofilm bacteria were of great significance. The related mechanisms of such influence need to be further studied and clarified in depth to consider epinecrotic biofilm as a reliable predictor in the forensic investigations.

Microbial community succession of submerged bones in an aquatic habitat.

After death, microbes (including bacteria and fungi) colonize carrion from a variety of sources during the decomposition process. The predictable succession of microbes could be useful for forensics, such as postmortem submersion interval estimation (PMSI) for aquatic deaths. However, gaps exist in our understanding of microbial succession on submerged bone, particularly regarding longer-term decomposition (>1year), fungal composition, and differences between internal and external microbial communities. To further explore this potential forensic tool, we described the postmortem microbial communities (bacteria and fungi) on and within submerged bones using targeted amplicon sequencing. We hypothesized predictable successional patterns of microbial colonization would be detected on the surface and within submerged bones, which would eventually converge to a similar microbial community. To best replicate forensic contexts, we sampled bones from replicate swine (Sus scrofa domesticus) carcasses submerged in a freshwater pond, every three months for nearly two years. Microbial bone (internal vs. external) community structure (taxa abundance and diversity) of bones differed for both bacteria and fungi, but internal and external communities did not converge to a similar structure. PMSI estimation models built with random forest regression of postmortem microbiomes were highly accurate (>80% variation explained in PMSI) and showed promise for forensic purposes. Overall, we provide further evidence that internal and external bone microbial communities submerged in an aquatic habitat are distinct and each community undergoes predictable succession, demonstrating potential utility in forensics for modeling PMSI in unattended deaths and/or cold cases.

Inferring Postmortem Submersion Interval in Rats Found in Water Based on Vitreous Humor Metabolites.

The metabolomics technique of LC-MS/MS combined with data analysis was used to detect changes and differences in metabolic profiles in the vitreous humor of early rat carcasses found in water, and to explore the feasibility of its use for early postmortem submersion interval (PMSI) estimation and the cause of death determination. The experimental model was established in natural lake water with 100 SD rats were randomly divided into a drowning group (n=50) and a postmortem (CO2 suffocation) immediately submersion group (n=50). Vitreous humor was extracted from 10 rats in each group at 0, 6, 12, 18 and 24 h postmortem for metabolomics analyses, of which 8 were used as the training set to build the model, and 2 were used as test set. PCA and PLS multivariate statistical analysis were performed to explore the differences in metabolic profiles among PMSI and causes of death in the training set samples. Then random forest (RF) algorithm was used to screen several biomarkers to establish a model. PCA and PLS analysis showed that the metabolic profiles had time regularity, but no differences were found among different causes of death. Thirteen small molecule biomarkers with good temporal correlation were selected by RF algorithm. A simple PMSI estimation model was constructed based on this indicator set, and the data of the test samples showed the mean absolute error (MAE) of the model was 0.847 h. The 13 metabolic markers screened in the vitreous humor of rat corpses in water had good correlations with the early PMSI. The simplified PMSI estimation model constructed by RF can be used to estimate the PMSI. Additionally, the metabolic profiles of vitreous humor cannot be used for early identification of cause of death in water carcasses.

Review and Prospect of Diagnosis of Drowning Deaths in Water.

Drowning is the death caused by asphyxiation due to fluid blocking the airway. In the practice of forensic medicine, it is the key to determine whether the corpse was drowned or entered the water after death. At the same time, the drowning site inference and postmortem submersion interval (PMSI) play an important role in the investigating the identity of the deceased, narrowing the investigation scope, and solving the case. Based on diatoms testing, molecular biology, imaging and artificial intelligence and other technologies, domestic and foreign forensic scientists have done relative research in the identification of the cause of death, drowning site inference and PMSI, and achieved certain results in forensic medicine application. In order to provide a reference for future study of bodies in the water, this paper summarizes the above research contents.

Bibliometrics Analysis in English and Chinese Literature on Drowning in Forensic Medicine from 1991 to 2020.

To explore the research hotspots and development trends of the field of forensic drowning from 1991 to 2020 by bibliometrics methods. Based on Web of Science, CNKI database, Wanfang Data knowledge service platform, python 3.9.2, CiteSpace 5.8.R3, Gephi 0.9.2, etc. were used to analyze the publishing trends, countries/regions, institutions, authors and topics of the study on drowning. A total of 631 English literature were obtained, including 59 articles from Chinese authors, and 386 Chinese literature were obtained. The Chinese and English journals with the largest number of related literatures were Chinese Journal of Forensic Science (80 articles) and Forensic Science International (106 articles), respectively. Japan published the most articles in English, and China ranked third. Osaka City Univ (Japan, 28 articles) published the most English articles, and Guangzhou Forens Sci Inst (China, 22 articles) ranked second. Among Chinese literature, Guangzhou Forens Sci Inst (32 articles) published the most. The topic analysis of Chinese and English literature showed that diatom examination, virtual autopsy, postmortem biochemical examination, the nature of death, and postmortem submersion interval were the hot spots of current research, but English literature had more studies on new technologies and methods, while Chinese literature was more inclined to practice, application and experience summary. The number of literature in forensic medicine on drowning is relatively stable. The scope of international and domestic collaborations in this field is still limited. The automated examination of diatoms, the establishment of diatom DNA barcodes and virtual autopsy will be the most important research hotspots in the coming period and are expected to achieve breakthroughs in drowning diagnosis, drowning location inference, postmortem submersion interval estimation, etc.

A preliminary study on early postmortem submersion interval (PMSI) estimation and cause-of-death discrimination based on nontargeted metabolomics and machine learning algorithms.

Postmortem submersion interval (PMSI) estimation and cause-of-death discrimination of corpses in water have long been challenges in forensic practice. Recently, many studies have linked postmortem metabolic changes with PMI extension, providing a potential strategy for estimating PMSI using the metabolome. Additionally, there is a lack of potential indicators with high sensitivity and specificity for drowning identification. In the present study, we profiled the untargeted metabolome of blood samples from drowning and postmortem submersion rats at different PMSIs within 24 h by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 601 metabolites were detected. Four different machine learning algorithms, including random forest (RF), partial least squares (PLS), support vector machine (SVM), and neural network (NN), were used to compare the efficiency of the machine learning methods. Nineteen metabolites with obvious temporal regularity were selected as candidate biomarkers according to "IncNodePurity." Robust models were built with these biomarkers, which yielded a mean absolute error of 1.067 h. Additionally, 36 other metabolites were identified to build the classifier model for discriminating drowning and postmortem submersion (AUC = 1, accuracy = 95%). Our results demonstrated the potential application of metabolomics combined with machine learning in PMSI estimation and cause-of-death discrimination.

Study on Carcass Decomposition, Insect Succession in Aquatic Habitat and its Application in the Estimation of Post-Mortem Submersion Interval (PMIS)

Study on Carcass Decomposition, Insect Succession in Aquatic Habitat and its Application in the Estimation of Post-Mortem Submersion Interval (PMIS)

Microbial community succession on submerged vertebrate carcasses in a tidal river habitat: Implications for aquatic forensic investigations.

Death investigations in aquatic ecosystems are challenging due to abiotic and biotic factors that may influence the estimation of a postmortem submersion interval (PMSI). In this study, we examined bacterial changes throughout the decomposition process on porcine carcasses submerged in a tidal-influenced river and identified predictors of epinecrotic community succession. Fetal porcine (Sus scrofa) carcasses (N=6) were submerged with epinecrotic samples collected every 3days (6 collections) over a period of 19days (~7415 accumulated degree hours (ADH)). Amplicon sequencing was performed using the Illumina MiSeq platform (16S V4 region, 2×250bp format) to identify changes in bacterial relative abundance and diversity. To match bacterial succession with rough taphonomy, carcasses were visually assessed at each sampling time point to determine the decomposition stage. Notably, the three most abundant families were Moraxellaceae, Burkholderiaceae (Proteobacteria), and Clostridiaceae (Firmicutes), though communities composition varied significantly across decomposition stages. Greater bacterial phylogenetic diversity was observed in in latter decomposition stages (advanced floating decay, sunken remains). Random Forest Models were built to predict ADH and explained 77%-80.8% of variation in ADH with an error rate of +/-1943.2 ADH (Root Mean Square Error) or approx. ±2.7days at the mean water temperature of this study. This study provided a useful model that could be used to estimate a PMSI in this river system utilizing bacterial community succession, and thus, potentially improve the accuracy of such estimations to be used in the court of law.