gary hilton's mind was oddly creative, sometimes in ways that other cops didn't quite get. owing it hadn't got much news coverage, hatched a plan on the way to the interview. >> we are not going to tell him that she's dead. and that we were there investigating a missing person. >>reporter: just a funny chat about a missing woman, a missing ex girlfriend. if he was involved, how would he react? give something away, maybe? >> there was no giving of miranda rights, he was in his own home, voluntarily cooperating. he could've stopped the interview at any time but he opted not to do that. he wanted to speak and he did. >>reporter: so, asked the detectives, what did they do? >> we'd go out to dinner quite a bit. we went flying, took her sailing. we went skiing, locally, here. go out and go dancing. >>reporter: as for the relationship, it was exclusive, said doug, more or less. >> did she go out with other men? >> well, not to the best of my knowledge. at least when i was dating her. she used to kid me about it and say no, you don't have anything to worry about. but yeah, i guess s