Decomposition and insect succession of clothed and unclothed carcasses in Western Australia

The effect of clothing on carcass decomposition and patterns of insect succession onto remains were investigated in two separate years during autumn in Western Australia. The progression of decomposition differed between clothed and unclothed carcasses in both years of the study. The presence of clothing markedly prolonged the wet decay stage in both years with larval feeding occurring across the moist skin surface underneath clothing, as well as within and under the carcasses. Ambient temperatures were higher in the second year of the study and corresponded to marginally faster rates of decay throughout decomposition. Within years, insect arrival and oviposition were largely consistent between clothed and unclothed carcasses with a few notable exceptions. The green blow fly, Lucilia sericata Meigen (Diptera: Calliphoridae) oviposited one day earlier on clothed than unclothed carcasses in both years of the study. The black carrion fly, Australophyra rostrata Robineau-Desvoidy, (Diptera: Muscidae) colonised clothed carcasses in two distinct waves of succession but only one wave of ovipoistion was observed on unclothed carcasses in either year. Correspondingly, clothed carcasses supported larval feeding by A. rostrata for a longer duration than unclothed carcasses. Finally, dipteran larval masses were more widely distributed across the carcass surface and were present for a longer period of time on clothed carcasses than on unclothed carcasses in both years. Forensically relevant data detailing the seasonal pattern of insect succession onto clothed and unclothed decomposing remains in Western Australia are reported.     

Investigation into Seasonal Scavenging Patterns of Raccoons on Human Decomposition,

Although raccoons are known as one of the most common scavengers in the U.S., scavenging by these animals has seldom been studied in terms of forensic significance. In this research, the seasonal pattern of raccoon scavenging and its effect on human decomposition was investigated using 178 human cadavers placed at the Anthropological Research Facility (ARF) of the University of Tennessee, Knoxville (UTK) between February 2011 and December 2013. The results reveal that (i) the frequency of scavenging increases during summer, (ii) scavenging occurs relatively immediately and lasts shorter in summer months, and (iii) scavenging influences the decomposition process by hollowing limbs and by disturbing insect activities, both of which eventually increases the chance of mummification on the affected body. This information is expected to help forensic investigators identify raccoon scavenging as well as make a more precise interpretation of the effect of raccoon scavenging on bodies at crime scenes.     

Dynamic liveness and forgeries detection of the finger surface on the basis of spectroscopy in the 400-1650 nm region

Differentiation of living fingers, fake fingers and fingers from dead bodies was investigated using spectral analysis. For this purpose, reflection and transmission spectra in the wavelength region from 400 to 1650 nm were recorded from living volunteers and corpses. In an additional small test series (one living volunteer, three cadavers), time-resolved spectral images were prepared using reflectance (derived from pulse oximetry). The dynamic differences in the curves (including the absorption changes caused by the blanching effect and the pulse) provide initial approaches for the realisation of systems for liveness detection. Significant differences that would be useful for the integration into fingerprint recording systems of methods to defend against forgeries are discussed.     

The Effect of Clothing on the Rate of Decomposition and Diptera Colonization on Sus scrofa Carcasses

Twenty Sus scrofa carcasses were used to study the effect the presence of clothing had on decomposition rate and colonization locations of Diptera species; 10 unclothed control carcasses were compared to 10 clothed experimental carcasses over 58 days. Data collection occurred at regular accumulated degree day intervals; the level of decomposition as Total Body Score (TBS_surf), pattern of decomposition, and Diptera present was documented. Results indicated a statistically significant difference in the rate of decomposition, (t₄₂₇ = 2.59, p = 0.010), with unclothed carcasses decomposing faster than clothed carcasses. However, the overall decomposition rates from each carcass group are too similar to separate when applying a 95% CI, which means that, although statistically significant, from a practical forensic point of view they are not sufficiently dissimilar as to warrant the application of different formulae to estimate the postmortem interval. Further results demonstrated clothing provided blow flies with additional colonization locations.     

Decomposition of buried bodies and methods that may aid in their location

This is the second report on an ongoing study conducted to collect data on the decompositional rates of human cadavers and the first on buried cadavers. Six unembalmed human cadavers were buried separately in unlined trenches of various depths and allowed to naturally decompose for a time period ranging from a month to a year. During the period of burial, data were collected daily on the air, soil, and cadaver temperature at each burial site. At the end of each specified burial period the cadavers were exhumed and examined for the degree of decomposition which had taken place as well as changes in the soil pH, surface vegetation, and carrion insect activity. Analysis of the data shows that the decomposition rate of buried cadavers is highly dependent on the depth of burial and environmental temperatures. The depth at which the cadaver was buried also directly affected the degree of soil and vegetational changes as well as access by carrion insects. Application of this information can contribute to a more accurate estimation of time since death of a buried corpse and may aid in the location of such corpses.     

Predicting the postmortem interval using human intestinal microbiome data and random forest algorithm

Gradual changes in microbial communities in a human body after death can be used to determine postmortem interval (PMI). In this study, gut microflora samples were collected from the vermiform appendix and the transverse colon of human cadavers with PMIs between 5 and 192 h. The results revealed that the appendix might be an excellent intestinal sampling site and the appendix flora had an inferred succession rule during human body decomposition. Firmicutes, Bacteroidetes, and their respective subclasses showed a predictable succession rule in relative abundance over time. A Random Forest regression model was developed to correlate human gut microbiota with PMI. We believe that our findings have increased the knowledge of the composition and abundance of the gut microbiota in human corpses, and suggest that the use of the human appendix microbial succession may be a potential method for forensic estimation of the time of death.     

Occurrences of flesh flies (Diptera: Sarcophagidae) on human cadavers in Switzerland, and their importance as forensic indicators

From 1993 to 2008, criminal investigations were conducted in the western part of Switzerland with special attention to blowfly and flesh fly species in order to estimate the post-mortem interval when requested by the police authorities. Flesh flies were found in only 33 cases out of 160. Five species of the genus Sarcophaga were identified (S. africa, S. argyrostoma, S. caerulescens, S. similis and S. sp.). The main species found on corpses (larval stage) was S. argyrostoma. The thermal constant (K) calculated for this species in Switzerland is 380.6 ± 16.3 (mean ± S.D.) degree-days. With the exception of S. caerulescens, found three times in the larval stage on corpses, the three other species are of minor forensic importance. S. argyrostoma is found during summer and indoors. This species colonises dead bodies, usually the same day as blowfly species, and it could be used to estimate the post-mortem interval. Other species are discussed in the light of current knowledge on their biology and ecology. It is recommended that voucher material be deposited in a museum, allowing further studies by relevant specialists, thereby helping investigators and avoiding misidentifications.     

A new method of reproduction of fingerprints from corpses in a bad state of preservation using latex

In view of the problems arising while fingerprinting corpses in a bad state of preservation, especially in case of mummification and carbonization, the authors propose an innovative technique which uses latex film. To better illustrate the potential of the method, two cases where the latex technique was applied successfully are reported: the first one is a mummified body discovered in a shack on the outskirts of Milan and the second one is the case of a burnt corpse found in a car boot. Such a technique is versatile, easy to apply, and allows the operator to work quickly on cadavers without amputating parts, except in rare cases (i.e., burnt bodies with muscle retraction). By the latex technique, a perfect and enduring negative copy of the fingerprint is obtained, ready to be inked and photographed. The numerous copies produced this way can be inked several times allowing for the repeatability of the procedure and this is crucial in cases of problematic legal identification of corpses. In both the cases illustrated, the fingerprints obtained by the latex technique were useful for identification. The quality was good enough for the automatic fingerprint identification system research system to be applied.     

Extent of burn lesions--an analysis of 68 burned cadavers]

The burned bodies (n = 68) autopsied at the Freiburg Institute of Forensic Medicine in the years 1996-2001 (until the end of February) were examined with regard to the extent of consumption by the fire using the classifications suggested by Eckert et al., Maxeiner, Glassman and Crow, and Gerling et al. Further classification parameters were exposure of the body cavities and amputation of extremities as a result of the fire. Most cases were accidental deaths (approximately 75%). The fires occurred mainly in buildings (57%) or vehicles (34%); in 6 cases the burning took place in the open air. In most cases the degree of consumption by the fire was slight to moderate. Only 15% of the burned bodies showed extensive destruction with severe loss of soft tissue and shrinking or amputation of the extremities. In one case the soft tissue was completely destroyed with fragmentation of the calcined skeletal remains. In bodies recovered from house fired the extent of consumption by the fire was usually less pronounced than in bodies retrieved from burned-out vehicles.     

Rectal temperature time of death nomogram: dependence of corrective factors on the body weight under stronger thermic insulation conditions.

Ninety-eight test coolings were made under various cooling conditions (moving air, two types of both clothing and covering) on dummies of real masses of 1, 3.3, 9.9, 24.5 and 33.4 kg, respectively, which cool under standard conditions (unclothed, uncovered, still air) like human bodies of 14, 33, 41, 83 and 104 kg, respectively. The results provide evidence of a non-linear dependence of corrective factors of body weight upon the body weight. The dynamics of the dependence increases with the thickness of thermic insulation. Transferred to the use of the nomogram method on bodies, cooling conditions requiring corrective factors between 0.75 (moving air) and 1.3 (rather thin clothing/covering), known from experience on bodies of an average weight, can be used as in the past, independent of the body weight. According to experience the dependence of corrective factors on the body weight must be taken into account in bodies of a very high or low body weight. For that purpose both a simplified table and a formula for computing is given.     

Clothed and unclothed human figure drawings lead to more correct and incorrect reports of touch in children

Abstract

The purpose of the current study was to examine the effect of clothed and unclothed human figure drawings (HFDs) on children's reports of touch. Eighty 4/5-year-olds and 80 9/10-year-olds participated in a staged event in which measurements of their body parts (e.g. waistline) were taken. Specifically, they were touched on 10 different locations. Immediately or three weeks after the event, they had to report where they had been touched. Half of the children received a clothed HFD while the other half was provided with an unclothed HFD to assist children in their recall. When we compared children's recall before and after the presentation of a HFD, we found that clothed and unclothed HFDs significantly decreased the accuracy of children's reports of touch. So, although children reported more correct touches after the presentation of a HFD, they were also more likely to include more incorrect information in their reports of touch.     

Long persistence of rigor mortis at constant low temperature

We studied the persistence of rigor mortis by using physical manipulation. We tested the mobility of the knee on 146 corpses kept under refrigeration at Torino's city mortuary at a constant temperature of +4 degrees C. We found a persistence of complete rigor lasting for 10 days in all the cadavers we kept under observation; and in one case, rigor lasted for 16 days. Between the 11th and the 17th days, a progressively increasing number of corpses showed a change from complete into partial rigor (characterized by partial bending of the articulation). After the 17th day, all the remaining corpses showed partial rigor and in the two cadavers that were kept under observation "à outrance" we found the absolute resolution of rigor mortis occurred on the 28th day. Our results prove that it is possible to find a persistence of rigor mortis that is much longer than the expected when environmental conditions resemble average outdoor winter temperatures in temperate zones. Therefore, this datum must be considered when a corpse is found in those environmental conditions so that when estimating the time of death, we are not misled by the long persistence of rigor mortis.     

The suitability of using domestic pigs (Sus spp.) as human proxies in the geophysical detection of clandestine graves

Research in many forensic science fields commonly uses domestic pigs (Sus spp.) as proxies for human remains, due to their physiological and anatomical similarities, as well as being more readily available. Unfortunately, previous research, especially that which compares the decompositional process, has shown that pigs are not appropriate proxies for humans. To date, there has not been any published research that specifically addresses whether domestic pigs are adequate human proxies for the geophysical detection of clandestine graves. As such, the aim of this paper was to compare the geophysical responses of pig cadavers and human donor graves, in order to determine if pigs can indeed be used as adequate human proxies. To accomplish this, ground penetrating radar (GPR) and electrical resistivity tomography (ERT) responses on single and multiple pig cadaver graves were compared to single and multiple human donor graves, all of which are in known locations within the same geological environment. The results showed that under field conditions, both GPR and ERT were successful at observing human and pig burials, with no obvious differences between the detected geophysical responses. The results also showed that there were no differences in the geophysical responses of those who were clothed and unclothed. The similarity of the responses may reflect that the geophysical techniques can detect graves despite what their contents are. The study implications suggest that experimental studies in other soil and climate conditions can be easily replicated, benefiting law enforcement with missing persons cases.     

Experimental validation of forensic evidence: a study of the decomposition of buried pigs in a heavy clay soil.

In a murder investigation, where the victim had been strangled and buried in a shallow grave, there were discrepancies between the post mortem interval (PMI) as estimated from entomological studies and estimations determined from other evidence. This inconsistency provided the impetus for examining the decay process using pig carcasses as analogues for the human cadaver. The pigs were buried in the immediate vicinity of the original burial site in December 1996, which was the month when the victim was purported to have been interred in the previous year. The buried pigs were then monitored for 5 months which, based on the evidence other than the entomological, was the period over which the corpse was thought to have lain in the ground. The pig corpses were disturbed by scavengers in mid April: this was the same time that the human corpse was discovered in the previous year by scavengers. Insects played no role in the decomposition process until the pig carcasses had been exposed by animals. Blowflies, notably Calliphora vomitoria, were attracted to the exposed tissues and laid eggs from which larvae developed. Calliphora vomitoria is a species often used to estimate PMI. This investigation has shown that soil conditions and low seasonal temperatures had preserved the pig carcasses for longer than might be expected. Using the blowfly larvae to estimate PMI would have produced erroneous results had not the burial environment and exhumation history been investigated.     

Autolytic changes in blood cells of human cadavers. II. Morphological studies

The morphology of various types of cells in the peripheral blood of human cadavers was investigated. The material comprised 123 medicolegal autopsy cases with post-mortem (p.m.) times ranging from 1.7 to 270.4 hours. The corpses were kept at +4 °C. The haematocrit values of the blood increased rapidly after death. The haematocrit-corrected red cell count, and the total white cell and platelet counts remained quite stable during the whole p.m. time range. Red cells were quite rapidly transformed from a discoid configuration to crumbled discs, echinocytes and spherocytes, but no debris or burst cell configurations were seen. Rapid deterioration of the staining properties and marked morphological changes in many leucocytes occurred quite rapidly after death. Lymphocytes seemed to be the most resistant and basophils the least resistant to the effects of autolysis. Morphologically altered platelets and aggregates of them were seen in each cadaver.The present morphological observations and the quantitative results suggest that various cellular elements of the blood seem to be quite resistant to autolytic effects, and many cells apparently retain their viability for longer periods of time in the blood of cadavers kept at reduced temperature.     

Identification of decomposition volatile organic compounds from surface-deposited and submerged porcine remains

Cadaver dogs are routinely used internationally by police and civilian search organisations to locate human remains on land and in water, yet little is currently known about the volatile organic compounds (VOCs) that are released by a cadaver underwater; how this compares to those given off by a cadaver deposited on land; and ultimately, how this affects the detection of drowned victims by dogs. The aim of this study was to identify the VOCs released by whole porcine (Sus scrofa domesticus) cadavers deposited on the surface and submerged in water using solid phase microextraction gas chromatography mass spectrometry (SPME GC–MS) to ascertain if there are notable differences in decomposition odour depending on the deposition location.For the first time in the UK, the volatile organic compounds (VOCs) from the headspace of decomposing porcine cadavers deposited in both terrestrial and water environments have been detected and identified using SPME-GCMS, including thirteen new VOCs not previously detected from porcine cadavers. Distinct differences were found between the VOCs emitted by porcine cadavers in terrestrial and water environments. In total, seventy-four VOCs were identified from a variety of different chemical classes; carboxylic acids, alcohols, aromatics, aldehydes, ketones, hydrocarbons, esters, ethers, nitrogen compounds and sulphur compounds. Only forty-one VOCs were detected in the headspace of the submerged pigs with seventy detected in the headspace of the surface-deposited pigs. These deposition-dependent differences have important implications for the training of cadaver dogs in the UK. If dog training does not account for these depositional differences, there is potential for human remains to be missed.Whilst the specific odours that elicit a trained response from cadaver dogs remain unknown, this research means that recommendations can be made for the training of cadaver dogs to incorporate different depositions, to account for odour differences and mitigate the possibility of missed human remains operationally.     

Weal-formation by Utrica Dioica. An intravital reaction? (author's transl)]

The question concerning the intravital and postmortal mechanism of urticarial weal after contact with nettles (urtica dioica) was investigated in corpses, animal experiments and voluntary trials. No nettle weals could be induced in corpses or postmortally in experiments with albino rats (Witstar Strain). When animals were exposed to nettle-stings immediately before decapitation only 2 od 12 rats developed weals postmortally. However, the diameter of such weals was only 30% of that of weals produced intravitally. After Application of a tourniquet (180 - 200 mm Hg) to test persons no weals were formed after contact with nettles in a period of 10 minutes. As soon as the tourniquet was released weal-formation occured in full extent in most test persons. According to the authors opinion the occurence of nettle weals (urtica dioica) in corpses is therefore considered a local intravital reaction.     

Postmortem diagnosis of diabetes mellitus. Quantitation of fructosamine and glycated hemoglobin

Fructosamine and glycated hemoglobin were determined in samples from 52 cadavers autopsied in the Forensic Pathology Institute of the University of Copenhagen (Denmark). The population studied comprised 15 adult subjects with history of diabetes mellitus and 37 adult non-diabetic subjects. The fructosamine/total protein ratio was 1.7 times higher in diabetic than in non-diabetic subjects, as was the case for glycated hemoglobin. Measurement of glycated serum protein appears to be a useful tool for the postmortem diagnosis of fatal diabetic coma and glucose concentration before death.     

Portion size matters: Carrion ecology lessons for medicolegal death investigations—A study in Cape Town,South Africa

Forensic taphonomic studies are regionally specific and improve time since death estimates for medico-legal casework. Within forensic taphonomy and carrion ecology, vertebrate scavengers are under-researched with many studies conducted using multiple, unclothed carcasses. This is a forensically unrealistic experimental design choice with unknown impact. The effect of variation in carrion biomass on the decomposition ecosystem, particularly where vertebrate scavengers are concerned, requires clarification. To assess the effect of carrion biomass load on vertebrate scavenging and decomposition rate, seasonal baseline data for single, clothed ~60 kg porcine carcasses were compared to clothed multiple-carcass deployments, in a forensically relevant habitat of Cape Town, South Africa. Decomposition was tracked via weight loss and bloat progression and scavenging activity via motion-activated cameras. The single carcasses decayed more quickly, particularly during the cooler, wetter winter, strongly correlated with concentrated Cape gray mongoose (Galerella pulverulenta) scavenging activity. On average and across seasons, the single carcasses lost 68% of their mass by day 32 (567 accumulated degree days [ADD]), compared to 80 days (1477 ADD) for multi-carcass deployments. The single carcasses experienced substantially more scavenging activity, with longer visits by single and multiple mongooses, totaling 53 h on average compared to 20 h for the multi-carcass deployments. These differences in scavenging activity and decay rate demonstrate the impact of carrion biomass load on decomposition for forensic taphonomy research. These findings need corroboration. However, forensic realism requires consideration in taphonomic study design. Longitudinally examining many single carcasses may produce more forensically accurate, locally appropriate, and usable results.     

三维螺旋CT在机械性损伤尸体检验中的价值

目的应用三维螺旋CT对尸体进行检验,探索其对机械性损伤尸体的诊断能力及其优势,同时积累尸体CT检验的经验。方法对机械性损伤致死的10例尸体在解剖前行全身CT检验,随后在CT诊断的指导下进行尸体解剖,比较两者在损伤的诊断、显示效果方面的差异。结果尸体CT检验可以清晰显示身体各部位骨折及体腔内出血的三维形态特征,而且可以敏感的检查到全身各部位的积气,对于非常规解剖暴露的部位,在解剖前行CT检验可减少骨折的漏诊;对软组织内出血、器官破裂等未能形成明显X线密度差异的损伤,CT检验效果欠佳。结论对机械性损伤尸体的检验,CT有其特殊的价值,可作为尸体解剖前有效的补充,避免损伤的漏诊;对于某些无法进行尸体解剖的案件,CT检验所见可作为死亡原因判断以及致伤方式推断的参考依据。