Milwaukee prosecutors this week filed a rape charge against an assailant whose identity is known only by his DNA, a new tactic that prosecutors hope will allow rape cases to be prosecuted after their 6-year statute of limitations has passed. In this case, DNA samples taken from three rape victims showed that they were all raped by a single man, whose identity is known only by a string of DNA code. By filing the warrant now, prosecutors buy time to discover the identity of the attacker even after the statute of limitations has passed. Each month, an FBI computer will compare the DNA codes on this and other warrants with the DNA collected from suspected and convicted criminals around the country. The problem with DNA evidence, like other evidence in rape cases, is that crime units do not have the resources to process it. According to the New York Times, 180,000 rape kits containing various forms of physical evidence remain unexamined in the US.