“When you’re talking about investigating death scenes, there are very few types of physical evidence you can guarantee will be present at every scene,” Carter said. “You never know if there will be fingerprints, or bloodstains or camera footage. But the microbes will always be there.”
What’s more, these microbes can be particularly useful, Carter said, under the types of conditions examined in the new study. “We’re talking about outdoor death scenes,” he said. “It can be difficult to gather information in those types of investigations.”
The director of the National Institute of Justice, Nancy La Vigne, views the research as particularly promising. “One of the principal questions of any death investigation is ‘when did this person die?’” La Vigne said. “This continuing line of NIJ-funded research is showing promising results for predicting time of death of human remains, aiding in identification of the decedent, determining potential suspects and confirmation or refutation of alibis.”
In addition to identifying the universal decomposers, the research team also attempted to determine where this microbial community came from. Notably, Metcalf said, they couldn’t find the microbes in soil microbiome databases or catalogs of human skin and gut microbiomes. They did, however, find the universal decomposers on insects. “It seems like the insects are bringing the microbes in,” Metcalf said.