Case ReportCase report: Time of death estimation of a buried body by modeling a decomposition matrix for a pig carcass
Introduction
Estimating time of death of buried human bodies is a very difficult task. Casper’s rule from 1860 [1], [2] states (p.37): “At a tolerably similar average temperature, the degree of putrefaction present in a body after lying in the open air for one week (month) corresponds to that found in a body after lying in the water for two weeks (month), or after lying in the earth in the usual manner for eight weeks (or month).” It is still widely used [3], [4] which illustrates the lack of suitable methods. Characteristics of decomposition can be identified and distinguished [5] but it is nearly impossible to determine an accurate time of death or burial time based on these findings. Many factors such as pre-mortem conditions; cause of death; time between death and burial; and especially site dependent factors such as soil type and soil humidity influence decomposition of buried human remains [6].
To perform studies and calculate valid postmortem intervals in forensic cases a surrogate human body is needed: we propose to use pig carcasses to generate decomposition matrices for buried bodies in specific locations. The use of carcasses of properly anesthetized and euthanized animals without prior treatment is in many countries not considered an animal experiment (e.g. Germany (§7 TierSchG)). A decomposition matrix lists characteristics of decay and shows their appearance as a function of time.
In the present case study investigators failed to narrow down the possible time of death of a victim due to contradicting witness statements and the absence of suitable studies.
Section snippets
Case
On July 31 the body of a male of about 180 cm and 60 kg was found in an arbor; buried in soil within the back part of the wooden shed.
The owner of the garden had had an argument with her partner; in leaving the joint apartment the partner mentioned that the problem with a specific friend was solved. The woman grew suspicious as she hadn’t seen the friend in some time and the pit in her arbor – which was supposed to become a toilet – had been refilled for an unremembered time span without serving
08.08.2012: burial of the pig carcass
The pig was anesthetized using ketamine and midazolam and euthanized with pentobarbital shortly before it was buried within the pit the victim had been found in (Fig. 2). Rectal temperature was 39.01 °C (Table 1), which is consistent with normal core body temperature of pigs.
To analyze decomposition in a skin-skin contact zone similar to the one found on the left leg of the victim the hind legs of the pig’s carcass were tied together with a rope.
Ambient as well as soil temperature was measured
15.08.2012: 1. Excavation
Seven days after the burial the pig carcass was excavated for the first time. During this and all following excavations soil temperature was measured gradually from level to ground of the cavern. The carcass was removed from the pit and deposited onto a plastic tarp for further examination. As expected core temperature adapted to soil temperature and reached 15.78 °C (Table 1).
The soil was very moist, clayey and heavy on the surface as well as in the depth of the hole. No soil organisms or
Discussion
In this case report we estimated PMI for a buried human body by using a pig carcass as a model to generate a decomposition matrix (Table 2). We were able to limit the possible burial time of the victim to 2–3 weeks, where first assumptions considered 6 weeks. This result was later confirmed by a new witness.
Furthermore we showed that advanced decomposition stages can be reached after unexpectedly short time periods even in buried bodies. It is therefore vital to analyze each case very thoroughly
References (7)
Practisches Handbuch der Gerichtlichen Medicin nach eigenen Erfahrungen bearbeitet. Zweiter Band Thanatologischer Teil
(1860)Handbook of the practice of forensic medicine, based upon personal experience. Thanatological Division
(1861)- et al.
Handbuch Gerichtliche Medizin
(2004)
Cited by (9)
Estimation of post-mortem interval based on insect species present on a corpse found in a suitcase
2020, Forensic Science InternationalCitation Excerpt :At present, the most successful determinations have been in estimations of the minimum PMI (PMImin) based on the developmental stage of the insects found on the corpse [5]. Forensic entomologists encounter corpses under various environmental conditions, including those exposed to the soil surface, buried [6–9], floating [10], burnt [11], located indoor or outdoor [12–15], wrapped [16,17], found in high-rise buildings [18], and found in a variety of other environments. In each situation, insects may colonize the corpse in different ways, so different influencing factors need to be considered when inferring the time of death.
Application of a Photoacoustic Tomography System: A Case Study on the Monitoring of Pig Tissue Decomposition
2022, Makara Journal of ScienceLarge animal models in forensic medicine and pathology: Recent research and its impact on the evolution of veterinary forensic pathology
2020, Archives of Hellenic MedicineEvaluation of soil chemical properties during cadaveric decomposition and its applications to forensic chemistry
2018, Revista Virtual de Quimica