. >> in 1995, detective derrick mclaughlin reopens the case.ch has been cold for ten years. >> my chief at the time came up to me with this box filled with binders and notes and things of that nature, and he said this was the zarcyzki case, solve it. >> the father of cindy's boyfriend, scott. >> he asked us to meet him up at the dairy queen. for a surprise birthday party for scott. and i guess the birthday party was just a roos to get her to go with him. >> the detective soon discovers that he's a convicted criminal and is in prison. >> he was convicted of indecent liberties with a minor. and he served in 1975 to 1978, he served three years in prison. after that, he was out and about all the way up until 1997 when he was convicted of the rape of the 13-year-old girl. >> detective mclaughlin believes he's found cindy's killer. >> i'm theorizing that he had picked her up, taken her to a place, went to go rape her. she resisted. he tried to get her out of that situation. couldn't. and he killed her. >> but with no body, it takes 13 years of tenaci