last sighting? a colleague saw him driving his black mercedes. we felt that the vehicle was still out there somewhere. reporter: so find the car, and maybe find out what happened to gavin. and nine months after gavin vanished, they finally got the break they were looking for. i said, i m here to talk to you about your daughter. and he started crying. and he said, she saw everything. reporter: coming up. we waited until she showed up and kind of surprised her. very nervous. startled. a new witness and a game changer of a clue. i kissed my partner on the cheek. it was pretty exciting. big piece of evidence. huge moment. you think you can t be shocked. but you can be. when dark valley continues. .
all struggled with adridiction d serious financial problems. detectives were far from answers, but that would change when someone gave them a name that led to a crucial discovery. here s keith morrison with more. reporter: like it or not it s a fact, an element of human nature. some people have affairs. some of them just flings and others a lot. as they poked through his life. one name kept popping up. chandy. her full name, chandrika creech. she d already told the detectives that she and gavin had an affair years earlier. and that he called her right before he vanished. but now, nine months after gavin disappeared, the detectives got a tip.
learned, gavin had been unfaithful to his wife, had been seeing a woman named melanie, and now that gavin had disappeared without a trace we went to talk to her and to see if she had any information. did she? no. the relationship had ended, and she had not talked to him, and she had no idea where he was at. reporter: but though melanie was the reason gavin moved out of his house a month before he vanished, she was not his first affair. there had also been a woman named chandy. that relationship was years in the past, but phone records showed gavin called her on may 1st, the day before he disappeared. cops tracked her down, too. what did she tell you? she acknowledged the prior affair, and she said that she had not been in contact with him for some time, but then they started communicating via e-mail. and that would explain the fact that he called her on the phone? yes. reporter: but chandy said she didn t see him may 1st, hadn t heard from him since.
i m just thinking how in the [ bleep ] that i get in this situation. you know, i was scared for my life. reporter: and then gavin then got out of the mercedes, said creech. and there was something in his hand. it was like a ten to twelve-inch stainless steel thing that at the time i thought was a knife. we fell in the ground, and we went at it for about ten or fifteen seconds exchanging punches. at some point did you get that weapon? i kept punching him until he let go of it. okay. and what d you do with the weapon? i threw it over the back wall of my property. reporter: such a weapon was never recovered, by the way. but creech insisted there was one, a multi-purpose tool of some kind, and it was gavin who provoked the fight. i was defending my life. i didn t go there looking for a fight. i was just defending mine. i think he lied about everything that he said. reporter: on cross-examination, the prosecutor went straight for that so-called multipurpose tool. so
but made no connection between that and something she noticed about her boyfriend john creech. i discovered he had scrapes on his hands and on his arms. she didn t think he had anything to do with the disappearance. reporter: but when detective o brien heard about creech s scrapes, he immediately thought of gavin smith s wounds. he needed to talk to john creech again, and he found him in jail serving eight years on a cocaine charge. his second conviction for dealing drugs. not exactly an upstanding citizen. but could they prove he murdered gavin smith? we went to him, didn t ask him any questions, just put a picture down in front of him of the shallow grave with the wrapped up body. how did he react to that? very wide eyed, and the first phone call he made was to his attorney. that s hardly a surprise? no. reporter: but other phone calls were surprising. like the record of calls the detectives found in creech s cell phone from the night gavin vanished.