Postmortem Interval and Microbial Populations

According to a report by researchers at the Department of Entomology of Texas A&M University, microbes represent 99% of somatic cells in and on a human body … but can those organisms be used to predict the time since death?

A report recently made available online - the result of funds from NIJ - is titled “Development and Validation of Standard Operating Procedures for Measuring Microbial Populations for Estimating a Postmortem Interval” and was written by Jeffrey K. Tomberlin, Tawni L. Crippen, M. Eric Benbow, and Aaron M. Tarone.


"Predicting the postmortem interval of a decedent is a major task of law enforcement. Most methods implemented by death investigators rely on qualitative information (i.e., rigor mortis, livor mortis). Microbes represent 99% of somatic cells in and on a human body. No data are available on the use of these organisms to predict the time since death of a decedent, though it is known that certain chemicals, many of which are likely a result of microbial communities, are released by decomposing remains in a reliable pattern. Moreover, the effects of microbes on insect colonization of remains, sometimes the best predictor of a postmortem interval, are not understood. Because of a lack of understanding of microbial succession on decomposing human remains, no standard operating procedures (SOP) for sampling and using this information have been developed and validated. We developed a SOP for sampling and pyrosequencing bacteria communities on human remains to predict the actual time since death. We conducted a series of laboratory and field studies to achieve this end. The field studies will implement the SOP for sampling bacteria on decomposing human remains at the Forensic Anthropology Research Facility at Texas State University."

The full paper is available here.

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Court Case Update

FINGERPRINT EVIDENCE went through a nearly three-year ordeal in the New Hampshire court system, but eventually emerged unscathed. On April 4, 2008, the New Hampshire Supreme Court unanimously reversed the decision of a lower court to exclude expert testimony regarding fingerprint evidence in the case of The State of New Hampshire v. Richard Langill. The case has been remanded back to the Rockingham County Superior Court.