be. it can t be. i just kept hoping. i did everything i could. reporter: but even as she ran down leads, herself, it seem to tara that lisa, her sister-in-law, gavin s wife, wasn t searching. so he disappeared and you couldn t give up on the possibly he s out there somewhere and lisa could. and i wondered whether there were ever dark nights in your soul, i wonder if she had something to do with this. it crossed our minds all the time, i mean, it just did, did i think she could ever be the one responsible the physical, no, but somehow it kept playing back, why won t you search? why? the only way somebody doesn t look for you is if you already know definitively. reporter: yeah. they re no longer living.
van had to be gavin smith s. i kissed my partner on the cheek. that s a true story, it was big piece of evidence. when we were able to get closer and saw our entire crime scene in our opinion was in that car. reporter: crime scene, yes, suddenly all other theories seemed to fall away. the passenger s seat was completely covered in blood and at one point it was very eerie where you looked at the blood and you can see a hand mark of gavin smith as he died in that seat. reporter: soon the news reached the family. tara devastated. there is no going back from that? there is no going back. reporter: you accepted it? you know, you re forced. you know trauma happens to people all the time. you don t think it s going to happen to you. but it does. you know when you already expect the worst, you think that you can t be shocked, but you can be is all i can say about that.
Transcripts for MSNBC Dateline 20210807 09:12:30 archive.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from archive.org Daily Mail and Mail on Sunday newspapers.
retirement account and recklessly blowing through his six figure salary and there were other signs of strain in the family. in april, 2012, a month before gavin disappeared, his son evan wrote this message on twitter. thoughts and prayers out to my amazing mom and brothers, please. my dad decided to leave the family last night. real family sticks together. sister tara spoke with gavin at the time. he was struggling with losing what he had come to know and love for so many years and that was his family unit. and he didn t want to hurt those boys and that s what he kept saying. i don t want to be without them. reporter: but as much as he loved his boys, detectives learned, gavin had been unfaithful to his wife, had been seeing a woman named melanie and now that gavin had disappeared
reporter: and you must have had a reason for knowing that. that s what i assume. reporter: it turned out lisa did know something, just not what tara expected. there were secrets which lisa and gavin kept hidden. he adored me, our family was exactly what he wanted to have. it just got lost. reporter: lost. it all started in the early 80s even before she met gavin when he was a stunt man on the tv series remington steele, he played a shooting victim, falling from a second story window. the stunt went wrong and he broke his back. he would take pain pills for his back. so usually percocet, something like that for pain. when that didn t work anymore, he was prescribed oxycontin. and he was addicted to it. reporter: he went to a drug rehab center called the matrix institute, here in the san fernando valley.