A new study on microbes that appear on cadavers could help change the way murders are investigated. Researchers have for the first time identified a network of around 20 microbes that universally drive the decomposition of animal flesh, announced Colorado State University on Monday. This study could change the future of forensic science, giving investigators a more precise way to determine when a body died.
How they help solve murders
One of the most important things to find out during the investigation of a death or a murder is exactly when the person died. Predicting the time of death of human remains can help in identifying the deceased person, finding out potential suspects and can even help confirm or refute alibis.
However, estimating the time of death is not an easy task. Current methods rely on measuring the body temperature, rigor mortis, or insect activity, which can be affected by various factors such as weather, clothing, or location.
Microbes, on the other hand, offer a more reliable and accurate way to determine the postmortem interval (PMI), which is the time elapsed since death. As the body begins to decompose, microbial communities undergo predictable changes in composition and abundance over time. By studying these microbial changes, forensic scientists may be able to pinpoint when exactly a person died.
The universal network of decomposing Microbes
For the multi-year study, researchers decomposed 36 cadavers at three different facilities. They were decomposed in different climates and during all four seasons. They also collected skin and soil samples during the first 21 days for 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, researchers found the same set of nearly 20 specialist decomposing microbes on all 36 bodies. Also, these microbes seemed to arrive like clockwork at certain points through the observation period and insects played a key role.
“We see similar microbes arrive at similar times during decomposition, regardless of any number of outdoor variables you can think of,” said Jessica Metcalf, senior author of the new study published this week in the journal Nature Microbiology.
They used the data from the new study along with previous work and machine learning techniques to build a tool they claim can accurately predict the time since a body’s death.
“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. You never know if there will be fingerprints, bloodstains or camera footage. But the microbes will always be there,” said co-author David Carter in a press statement.
How microbes could transform forensic science
The discovery of the universal network of decomposing microbes could have significant implications for forensic science and criminal justice. It could provide a more objective and reliable way to estimate the time of death, which could help solve more cases and prevent wrongful convictions.
However, there are still some challenges and limitations to overcome before this method can be widely applied in practice. For instance, the study only focused on animal cadavers, not human ones. The researchers also acknowledge that they need to test their tool on more diverse samples and scenarios to validate its accuracy and robustness.
Moreover, there are ethical and legal issues that need to be addressed before using microbial data as evidence in court. For example, who owns the rights to access and use the microbial data? How can privacy and consent be ensured? How can quality control and standardization be achieved?
These are some of the questions that need further research and discussion before microbes can become the new detectives in murder investigations.
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