Researchers have for the first time identified a network of about 20 microbes that universally drive the breakdown of animal meat, Colorado State University announced Monday. This study could change the future of forensic science, giving investigators a more accurate way to determine when a body died.
“It’s really cool that there are these microbes that always appear to decompose animal remains. Hopefully, we’re opening up this whole new area of ecological research,” said Jessica Metcalf, lead author of a new study published this week in the journal Nature Microbiology.
For the multi-year study, researchers decomposed 36 corpses at three different facilities. They were decomposed in different climates and during the four seasons. They also collected skin and soil samples during the first 21 days of each decomposing body. After collecting a lot of molecular and genomic information from the samples, they created an overall picture of the “microbiome” present at each site. This was a report of what microbes were there, how they got there, and how that changes over time.
Interestingly, the researchers found the same set of nearly 20 specialized decomposer microbes in all 36 bodies. Additionally, these microbes seemed to arrive like clockwork at certain points during the observation period, and insects played a key role. “We see that similar microbes arrive at similar times during decomposition, regardless of the number of outside variables you can imagine,” Metcalf added.
They used data from the new study along with previous work and machine learning techniques to build a tool they say can accurately predict the time since a body died, a figure known as the “postmortem interval.”
“When it comes to investigating death scenes, there are very few types of physical evidence that can be guaranteed to be present at every scene. You never know if there will be fingerprints, blood stains or camera images. But the microbes will always be there,” co-author David Carter said in a press release.
One of the most important things to find out during a death or murder investigation is exactly when the person died. Predicting the time of death from human remains can help identify the deceased, uncover potential suspects, and can even help confirm or refute alibis.