Around 20 species of microorganisms
have been discovered
which at the
crime scene
allow us to
precisely reconstruct the time of the
victim's death: they are
fungi
and
bacteria
that appear on the corpse and decompose it with
well-defined times
, regardless of environmental factors such as the type of soil or the climate.
This is demonstrated by an American study funded by the National Institute of Justice (Nij) of the United States and published in the journal Nature Microbiology.
The researchers, coordinated by Jessica Metcalf of Colorado State University, monitored the decomposition process of 36 corpses donated to science and placed in three different forensic anthropology facilities in Colorado, Tennessee and Texas.
The study was conducted outdoors in different environmental and climatic conditions, in the four seasons, taking samples of the skin of the corpses and the surrounding soil in the first 21 days post-mortem.
Molecular and genomic analyzes made it possible to identify around twenty microorganisms specialized in decomposition, present on all 36 bodies regardless of the climate or the type of soil in which they were left.
These microorganisms appeared with very specific timing, probably transported by insects.
These data,
reprocessed with machine learning techniques,
have made it possible to develop a
new tool useful for forensic science
, a real '
microbiological clock
' which allows
the time of death to be established
.
“When it comes to investigating a death scene, there are very few types of physical evidence that are guaranteed to be there,” explains forensic science expert David Carter of Chaminade University in Honolulu.
“You never know if there will be fingerprints, bloodstains or camera footage.
But the microbes will always be there."
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