Shells and Bones: A Forensic Medicine Study of the Association of Terrestrial Snail Allopeas micra with Buried Human Remains in Brazil

Little is known regarding the scavenger fauna associated with buried human corpses, particularly in clandestine burials. We report the presence of 20 shells of the terrestrial snail Allopeas micra, within hollow bones of human remains buried for 5 years, during the process of collecting DNA material. The fact that a large number of shells of A. micra had been found in the corpse and in the crime scene supports the assumption that there was no attempt to remove the corpse from the area where the crime occurred. Despite this, our observations cannot be used to estimate the postmortem interval because there is no precise knowledge about the development of this species. This is the first record of a terrestrial snail associated with a human corpse and its role in this forensic medicine case.     

Investigation of homicides interred in concrete--the Los Angeles experience

Decedents interred in concrete present unique problems and investigation of these deaths necessitates a team of forensic specialists. The Los Angeles County Department of Coroner has had five such deaths in the past 18 years. The buried cases needed layer-by-layer excavation to establish the time and cause of death. Metal detectors are often used in this process. X-rays of the interred remains were completed to help with locating the decedent's position in the concrete. The breaking of concrete in some of the cases required the use of a sledgehammer and later a chisel in a manner that would not damage the remains. Postmortem dismemberment was frequent in our cases. The decedents were all female or prepubescent children, and the perpetrators were closely related to the decedents. While concrete can interfere with determination of postmortem interval, it can also preserve the remains and assist with identification.     

Collembola of the grave: a cold case history involving arthropods 28 years after death

This report describes a cold case in which a cadaver of a 28-year-old female was exhumed in February 2005 from a cemetery in Battle Creek, Michigan. She had sustained a gunshot wound to the head and was found dead in her home on November 15, 1977. The body of the victim was subsequently embalmed and then buried at a depth of 1.8 m in an unsealed casket that was placed inside an unsealed cement vault. The exhumation yielded thousands of live specimens of a single species of the order Collembola or spring tails, Sinella (Coecobrya) tenebricosa (Entomobryidae). This species is considered to be a "tramp" species, cosmopolitan in the United States and Canada. Due to the ideal environmental conditions at the site, the population of this species underwent growth and development inside the casket for a number of years. Collected with the Collembola were large numbers of Acarina (mites) of the Family Glycyphagidae, and fly puparia, Conicera tibialis Schmitz (Order: Diptera, Family: Phoridae), also known as coffin flies. These invertebrates are sometimes mentioned by forensic investigators as occurring on corpses in graves, but aspects of their life history are rarely described. The species of Collembola that was found surviving and reproducing on this corpse in a casket exhumed after 28 years was the oldest reported grave site occurrence for any collembolan species based on a survey of the literature back to 1898.     

A New Method for Determination of Postmortem Interval: Citrate Content of Bone*

Abstract: Few accurate methods exist currently to determine the time since death (postmortem interval, PMI) of skeletonized human remains found at crime scenes. Citrate is present as a constituent of living human and animal cortical bone at very uniform initial concentration (2.0 ± 0.1 wt %). In skeletal remains found in open landscape settings (whether buried or not), the concentration of citrate remains constant for a period of about 4 weeks, after which it decreases linearly as a function of log(time). The upper limit of the dating range is about 100 years. The precision of determination decreases slightly with age. The rate of decrease appears to be independent of temperature or rainfall but drops to zero for storage temperature <0°C.     

Identification of Crystals Forming on Porcine Articular Cartilage: A New Method for the Estimation of the Postmortem Interval

Articular cartilage was examined to determine its decomposition sequence and its potential for assessing the postmortem interval. Scanning electron microscopy of articular cartilage from buried porcine trotters showed the presence of microcrystals on the synovial surface. These orthorhombic pyramidal or “coffin”‐shaped crystals, appeared at 3 weeks (22 days) after interment and disappeared after 6 weeks. The disappearance of these crystals was linked to decompositional changes to the integrity of the synovial joint. The formation and disappearance of these crystals was associated with a pH change at the cartilage surface. Scanning electron microscopy–energy‐dispersive X‐ray (SEM‐EDX) analysis showed that the five main elements contained within these crystals were carbon, nitrogen, oxygen, magnesium, and phosphorous. Such elemental analysis suggested the crystals may be struvite (MgNH₄PO₄6(H₂O)). Bacteria cultured from the cartilage synovial surface produced struvite crystals when grown in suitable media and were identified by DNA analysis to be Comamonas sp.     

Soilwater Conductivity Analysis to Date and Locate Clandestine Graves of Homicide Victims

In homicide investigations, it is critically important that postmortem interval and postburial interval (PBI) of buried victims are determined accurately. However, clandestine graves can be difficult to locate; and the detection rates for a variety of search methods (ranging from simple ground probing through to remote imaging and near‐surface geophysics) can be very low. In this study, simulated graves of homicide victims were emplaced in three sites with contrasting soil types, bedrock, and depositional environments. The long‐term monthly in situ monitoring of grave soil water revealed rapid increases in conductivity up to 2 years after burial, with the longest study evidencing declining values to background levels after 4.25 years. Results were corrected for site temperatures and rainfall to produce generic models of fluid conductivity as a function of time. The research suggests soilwater conductivity can give reliable PBI estimates for clandestine burials and therefore be used as a grave detection method.     

The Influence of Preburial Insect Access on the Decomposition Rate

Abstract: This study compared total body score (TBS) in buried remains (35 cm depth) with and without insect access prior to burial. Sixty rabbit carcasses were exhumed at 50 accumulated degree day (ADD) intervals. Weight loss, TBS, intra‐abdominal decomposition, carcass/soil interface temperature, and below‐carcass soil pH were recorded and analyzed. Results showed significant differences (p << 0.001) in decomposition rates between carcasses with and without insect access prior to burial. An approximately 30% enhanced decomposition rate with insects was observed. TBS was the most valid tool in postmortem interval (PMI) estimation. All other variables showed only weak relationships to decomposition stages, adding little value to PMI estimation. Although progress in estimating the PMI for surface remains has been made, no previous studies have accomplished this for buried remains. This study builds a framework to which further comparable studies can contribute, to produce predictive models for PMI estimation in buried human remains.     

Citrate Content of Bone for Time Since Death Estimation: Results from Burials with Different Physical Characteristics and Known PMI

A recently introduced method to determine the postmortem interval (PMI) based on quantification of the citrate content in bone was applied on the temporal bones and femora of 20 individuals buried in wooden coffins (WO) and body bags (BB), respectively. Concerning known vs. calculated PMI, a significant difference between the temporal and the femur bone samples of the same individuals was observed in the BB group (p = 0.012). In contrast, differences were insignificant for the WO group (p = 0.400). Moreover, similar levels of underestimation of PMIs resulted from the analysis of the femora for both burial groups (p = 0.247). Also, there was consistently less citrate preserved in the flat temporal bones as compared to the femora, indicating that the cortical layer of the long bones should be preferentially employed for citrate‐based PMI estimations. The results call for additional research on subsurface‐buried and surface‐deposited remains to enhance the accuracy of the published PMI equation.     

The Applicability of the Lamendin Method to Skeletal Remains Buried for a 16-Year Period: A Cautionary Note

The Lamendin method is widely reported as one of the most reliable means of age estimation of skeletal remains, but very little is known concerning the influence of burial in soil. This study aimed at verifying the reliability of the Lamendin method on corpses buried for 16 years in a cemetery. The Lamendin and the Prince and Ubelaker methods were applied. In all age groups except the 40- to 49-year–olds, the error was higher in the buried sample. The age-at-death error ranged between 10.7 and 36.8 years for the Lamendin method (vs. the reported 7.3–18.9 years) and 9.5 and 35.7 for the Prince and Ubelaker one (vs. the original 5.2–32.6 years); in all age groups, the error is closer to that found on archeological populations. These results suggest caution in applying the Lamendin method to forensic cases of human remains buried even for a brief period under soil.     

Dynamics of Ninhydrin‐Reactive Nitrogen and pH in Gravesoil During the Extended Postmortem Interval

Estimating the postmortem interval of skeletal remains is difficult, as few tools exist to do so. To address this problem, we conducted a field experiment to measure the chemistry of swine (Sus scrofa domesticus Linnaeus) gravesoil after 1 year and 3 years postmortem. Carcasses were placed on the soil surface of a pasture during June in a cold (Dfa) climate. Significant (p < 0.05) increases in ninhydrin‐reactive nitrogen, pH, total nitrogen, and nitrate in gravesoil were detected 1 year postmortem. Significant differences in gravesoil chemistry were not detected 3 years postmortem. These observations coincided with gaps in plant growth 1 year postmortem and the development of lush vegetation 3 years postmortem. We conclude that these phenomena can be used to assist the decision‐making process regarding the allocation of resources during the early stages of a death investigation.     

Taphonomic Patterning of Cemetery Remains Received at the Office of the Chief Medical Examiner,Boston, Massachusetts

A sample of 49 cases of cemetery remains received at the Office of the Chief Medical Examiner, Massachusetts (OCME‐MA), in Boston was compared with published taphonomic profiles of cemetery remains. The present sample is composed of a cross section of typical cases in this region that ultimately are derived from modern to historical coffin burials and get turned over to or seized by law enforcement. The present sample was composed of a large portion of isolated remains, and most were completely skeletonized. The most prevalent taphonomic characteristics included uniform staining (77.6%), coffin wear (46.9%), and cortical Exfoliation (49.0%). Other taphonomic changes occurring due to later surface exposure of cemetery remains included subaerial weathering, animal gnawing, algae formation, and excavation marks. A case of one set of skeletal remains associated with coffin artifacts and cemetery offerings that was recovered from transported cemetery fill is also presented.     

Insect Successional Pattern of a Corpse in Cooler Months of Subtropical Southeastern Texas

Abstract:  Here, we characterize the cool weather insect fauna found associated with partially skeletonized and desiccated human remains recovered from an abandoned house in an urban area of subtropical, coastal Galveston County, Texas, and use the information to conclude an approximate postmortem interval of 7–10 months. The predominant factors that allow for a confident assessment of the postmortem interval include climatological data, entomological data, and anthropological data. The documented insect fauna represents a unique assemblage present in a particular environment (an urban abandoned house in coastal Texas) at a particular time of year (winter) and includes expected forensically significant insects such as calliphorid flies, muscid flies, and dermestid beetles but also includes less commonly encountered insects such as an unusually dense population of live case-making clothes moths.     

Preliminary Observations of Arthropods Associated with Buried Carrion on Oahu

Several studies in Hawaii have focused on arthropod succession and decomposition patterns of surface remains, but the current research presents the first study to focus on shallow burials in this context. Three domestic pig carcasses (Sus scrofa L.) were buried at the depths of 20–40 cm in silty clay loam soil on an exposed ridge on the leeward side of the volcanically formed Koolau Mountain Range. One carcass was exhumed after 3 weeks, another after 6 weeks, and the last carcass was exhumed after 9 weeks. An inventory of arthropod taxa present on the carrion and in the surrounding soil and observations pertaining to decomposition were recorded at each exhumation. The longer the carrion was buried, the greater the diversity of arthropod species that were recovered from the remains. Biomass loss was calculated to be 49% at the 3‐week interval, 56% at the 6‐week interval, and 59% at the 9‐week interval.     

大鼠死后腓肠肌直接电兴奋性变化与早期死亡时间的关系

目的探讨大鼠死亡后不同时间腓肠肌电兴奋性的变化,为早期死亡时间的推断提供新的指标。方法建立大鼠机械性窒息模型,利用电生理检测仪检测死亡后不同时间大鼠腓肠肌对不同强度的电刺激的反应性,记录肌肉组织动作电位出现时间,统计学分析其差异并建立回归方程。结果大鼠机械性窒息死亡后一定时间内,其腓肠肌对电刺激的兴奋性与死亡时间呈明显线性关系。结论肌肉组织的电兴奋性可以作为早期死亡时间推断的有效指标。     

The Effects of Soil Environment on Postmortem Interval: A Macroscopic Analysis

Abstract:  Burial environment, in particular soil moisture, has a significant impact on the type, rate, and extent of bone degradation, which ultimately affects estimations of the postmortem interval (PMI). The purpose of this research is to determine the effects of soil moisture on the color, weight, condition, and texture of bone as it relates to the PMI. Bone changes occurring over two different time intervals (2 and 5 months) were examined using 120 sus scrofa leg bones. During each time interval bones were buried in two soil environments, one of which was drier than the other. The bones in both environments lost weight over time but the net weight loss was greater for bones in the higher moisture environment. There was no change in color, texture, or overall condition, indicating that 150 days is not long enough for such alterations to occur, regardless of the moisture level of the burial environment.     

Putrefaction: An Additional Complicating Factor in the Assessment of Freshwater Drownings in Rivers

Background hypothesis: That bodies immersed in freshwater (rivers) may show greater changes of decomposition than bodies immersed in saltwater (sea). Fifty de‐identified river drownings and 50 sea drownings were randomly selected from autopsy files at Forensic Science SA, Adelaide, Australia and assessed for decomposition. Results: The river cases consisted of 43 males and seven females (M:F 6:1); age range of 2–92 years (mean 46.8 years); decomposition—16/50 (32%); postmortem interval 1–14 days, average 3.8. The sea cases consisted of 36 males and 14 females (M:F 2.6:1); age range of 9–81 years (mean 50.7 years); decomposition—2/50 (4%) (p < 0.001%); postmortem interval 1–6 days, average 2.8. As decomposition reduces information obtained at autopsy, postmortem examination of deaths in rivers may be less informative than deaths that have occurred in the sea. The reasons for less decomposition in the sea include cooler temperatures, exposure to salt and shorter postmortem intervals.     

Potential Use of Bacterial Community Succession in Decaying Human Bone for Estimating Postmortem Interval,,

Bacteria are taphonomic agents of human decomposition, potentially useful for estimating postmortem interval (PMI) in late‐stage decomposition. Bone samples from 12 individuals and three soil samples were analyzed to assess the effects of decomposition and advancing time on bacterial communities. Results indicated that partially skeletonized remains maintained a presence of bacteria associated with the human gut, whereas bacterial composition of dry skeletal remains maintained a community profile similar to soil communities. Variation in the UniFrac distances was significantly greater between groups than within groups (p < 0.001) for the unweighted metric and not the weighted metric. The members of the bacterial communities were more similar within than between decomposition stages. The oligotrophic environment of bone relative to soft tissue and the physical protection of organic substrates may preclude bacterial blooms during the first years of skeletonization. Therefore, community membership (unweighted) may be better for estimating PMI from skeletonized remains than community structure (weighted).     

The formation of early stage adipocere in submerged remains: a preliminary experimental study

In some circumstances, the presence of adipocere may retard decomposition and complicate postmortem interval estimation. This article explores the correlation between Accumulated Degree Days (ADD) and early stage formation of adipocere. Sixty wild rabbit (Oryctolagus cuniculus) carcasses were used in this experiment; a control group (N = 30) deposited directly on the ground surface and an experimental group (N = 30) completely submersed in water in individual buckets. Data (water and inner body temperature, pH, and total body score) were collected every 100 ADD. Results indicated that early stage adipocere is correlated to ADD and that its formation on submersed remains is more likely to occur after 630 ADD. Skin sloughing promoted the formation of adipocere. No adipocere was formed on any of the control group rabbits. This study also highlights the fact that multiple factors influence adipocere formation and it is suggested that further research needs to be conducted into this area.     

组织RNA检测用于死亡时间推断的研究进展

近几年来利用RNA的降解程度来推断死亡时间已逐渐成为法医学研究热点.本文复习相关研究文献,对大鼠不同组织(脑组织、心脏组织、肝脏组织和肾组织等)中RNA在推断死亡时间的具体应用方法做出总结,归纳出不同组织中的各类RNA在推断死亡时间方面的适用范围,以及对此种方法在推断死亡时间的过程中产生的问题及可行性的解决方法.     

尸源性昆虫的法医学研究进展

尸源性昆虫学是应用昆虫学知识解决有关法律问题的法医学分支学科,对死亡时间的推断。特别是腐败尸体的死后间隔时间的推断等方面具有无可比拟的优越性。本文根据国内外近期法医昆虫学方面的研究进展,阐述了尸源性昆虫的研究历史、种类和侵蚀过程,并总结了尸源性昆虫形态学及分子生物学的种属鉴定方法。及近几年来在推断死亡时间方面的具体应用。就尸源性昆虫在法医学领域内的应用及进展进行综述。