DNA evidence can tie possible suspects to crime scenes, but as Scientific American writes, over-reliance on such evidence can also be risky.
A case presented at the American Academy of Forensic Sciences meeting earlier this year illustrated just that: a homeless man, Lukis Anderson, was charged with the murder of a multimillionaire, Raveesh Kumra, based on DNA evidence, even though Anderson had an alibi — he was hospitalized that night. What happened, Scientific American reports, is that the paramedics who treated Anderson earlier in the evening were also at the scene of Kumra's murder and unintentionally brought Anderson's DNA with them.
Though DNA evidence is less subjective than some other forensic analyses like bite mark comparisons, it, too, is increasingly coming under scrutiny. New studies are showing just how far skin cells can travel and can place people's genetic material on items they never touched. That means, Scientific American says, that care should be taken in its interpretation and presentation to, for instance, a jury.
"Like all forms of evidence, DNA is only one circumstantial clue," Scientific American's Peter Andrey Smith writes. "As such, Anderson's case serves as a warning that a handful of wayward skin cells should not come to mean too much."