Decedent’s End-of-Life Condition and Toxicology May Alter Time-of-Death Estimation
by Douglas Ankney
Anthropology professor Dawnie Steadman, Director of the Forensic Anthropology Center at the University of Tennessee (“University”), and her colleagues “hypothesized that drugs found in decomposing bodies could have an influence on the behaviors of decomposers and result in differential rates of decomposition.” At the University’s Body Farm – “a 2.5-acre wooded property where researchers have been studying decomposition in a variety of natural settings” – researchers noticed an interesting phenomenon. “Human bodies donated for study and placed in the same environment at the exact same time were decomposing at different rates.” For example, there was heavy scavenging on some of the bodies while other bodies were entirely ignored. Insects colonized bodies at different times even though the bodies were in identical environments. And soil profiles revealed different chemical compounds among the individual bodies.
The varying characteristics of the bodies “appeared to enhance or disrupt decomposition.” This prompted the researchers “to question the accuracy of time-since-death approximations or the postmortem interval based on human and insect evidence.” Steadman and her team examined “the relationship between a donor’s drug use, end-of-life diseases, and their decomposition dynamics, which are affected by the behavior and presence of scavengers, insects, and intestinal microbes.” The researchers compared the toxicological drug screens of 22 cadavers with the drugs found in their associated decomposition fluid, in insect larvae, and in the surrounding soil samples.
The researchers discovered that drugs used for the treatment of neurological diseases resulted in a decrease of the diversity of microbial species found in the soil – indicating those drugs have a toxic effect on the soil microbes which may lead to a slower rate of decomposition. The same was true of decedents who had undergone treatment for cancer. However, decedents who had been treated for respiratory illness were associated with an increase in soil microbial diversity – suggesting the drugs used in treating these illnesses may lead to an increase in the rate of decomposition.
According to Danielle McLeod-Henning, a scientist with the National Institute of Justice, estimating the time of death is “one of the most important issues to address in any death investigation.” The estimation of the postmortem interval aids “in identification of the remains, and in cases of foul play, identifying potential suspects and confirming alibis.” While preliminary analysis of the research revealed “no statistically significant correlation between end-of-life condition, toxicology, and the accuracy of the time since death estimates,” the research may eventually modify postmortem interval estimates to account for the presence of particular drugs.
Source: forensicmag.com
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