Science Thursday

Researchers at the Southeast Texas Applied Forensic Science Facility have begun to look at bacteria on dead bodies to develop a

timeline for decomposition for forensic investigations.

The idea to use microbial bacteria to inform crime scene investigators about a person’s time of death originated from forensic entomology, a practice that studies the connection between insects and decomposition.  Sibyl Bucheli, a forensic entomologist from Sam Houston University, thought that if types of insects found at a crime scene change over time, so too could the bacteria.  Bucheli’s team is just beginning research that measures the changes of the bacterial environment during the decomposition process.  While the results are preliminary, Bucheli hopes that mapping out what concentration and types of bacteria are present could one day in the future provide an accurate indication of time of death. 

If crime scene investigators could reliably establish the time of death for a found body, police would have another point of reference to conduct investigations and to limit potential suspects. Since decomposition can be influenced by many variables, including the environment and exposure to sunlight, numerous studies will have to be completed to get a reliable and complete picture of how bacteria populations grow in different settings and climates.  However, time-of-death estimates have traditionally been difficult to gauge after 48 hours, so the potential of establishing a “microbial clock” is significant.

Bucheli and her team conduct their research on dead bodies that are placed on the ground in the woods at the Southeast Texas Applied Forensic Science Facility.  While developing a microbial clock is groundbreaking research, facilities that house dead bodies for scientific study, also known as “body farms,” have long been important research centers in the United States for those who study forensic entomology and taphonomy—the study of decomposition.

The global interest in developing academic research in forensic entomology and taphonomy is promising for forensic science.   Already, studies around the world, including a

recent one in Italy

that determined a timeline for water decomposition have added significant value to the field of taphonomy and forensic entomology. Recently, scientists in the United Kingdom pushed for the

creation of a decomposition facility

that can support local case studies and research. 

If continued efforts to understand and validate the appearance of bacteria at crime scenes continue, the estimation of time of death could become more accurate.