he tried to choke her a few times. >> you mean, during the session? >> during the session. >> police asked the woman to entice them and back to the ranch. >> well, when they came back the next session, the girl kept him talking, kept in classy, drinking, we turned him over to the police. >> they had dna was rushed to the crime lab, but it did not match the killer. investigation had started off so well, with so many clues about the killer, whose habits, his truck, his dna had now gone almost cold. the detectives pressed on, following more than 4000 leads, all of them to dead ends. but one day in november, 2008, ten months into the investigation, a detective was thumbing through yet another stack of tips. one of them caught his eye. >> one thing struck me as on, because they were talking about the underwear. >> the anonymous tip was about a woman who had found someone