checks on some of the people who attended the party in carolyn's apartment complex, including ynobe mathewsere were several police reports in the file accusing ynobe of a number of crimes. >> mr. matthews had a tendency to try to sexually assault females. and in the process of that, he would choke them if they were not willing to have sex with him. >> how did carolyn die? >> her death was ruled a strangulation. so things started kind of matching up. >> reporter: ynobe had never been convicted of sexual assault, but in the files the detective read the story one particularly brutal assault. a case ended up being charged as a misdemeanor -- unlawful restraint. it was kristin's. ynobe was the man she says almost killed her. >> i was certain that he had done this before. but at the same time i didn't think he would do it again. >> reporter: the detective called ynobe matthews back down to the station for another interview. decided to pull a fast one with his suspect, telling him he was about to get dna results from the crime scene. >> what -- were you really about to get it that quickly? >> we w