For example, researchers at the University of Colorado, Boulder took bacteria samples from computer keyboards.

They compared them to hand bacteria samples taken from the computers’ users, and to samples taken from people who’d never used the keyboards. The keyboard samples matched up much better with bacteria from the computer owners’ than they did with bacteria from strangers.

More studies need to be done to see if hand bacteria really are useful as a forensic tool. But as a complement to DNA and fingerprints, it could prove a reliable way to put away the bad guys.