Crime, genetalia, urine
Car thieves in Manchester, for example, have taken to dumping cigarette butts in stolen cars before they abandon them. "Suddenly the police have 20 potential people in the car," according to an expert interviewed in New Scientist.
So far, none of the thugs have hired Quentin Tarantino to direct a special blood-soaked, expletive-filled, happy slap - but surely it's only a matter of time.