In 1982 13 year old Kristin Sumstad was found raped, strangled and stuffed in a cardboard box. The killer got away with it for 20 years. In 2004 he was finally convicted. The killer was caught by the police when they sent him a letter telling him he had some money coming - he signed the form and then sealed the envelope (and his fate) by licking it and dropping it in the mail. Thus... the police had his DNA. Matched it up with the DNA they had in evidence from her body and viola..... murderer caught.
RIP Kristin - it's over.