The problem is that forensics requires a far higher threshold of certainty than skin bacteria are likely to provide. Foran notes that if a fingerprint is a 90% match to a questioned print, a forensic scientist would conclude that that person didn't leave the print. Likewise, a DNA sample that's 10% different would be a negative result, although in that case, you might look for a relative. He says, "The method presented will probably never lead to a match; given the huge amount of bacterial variability the authors find over time and even among different body parts, finding a true DNA match between questioned and knowns would be next to impossible. It would be far easier for the defense to argue that the suspect did NOT leave that bacterial profile."