>> kevin kyne is a name on paper. that man is not a kyne.for diane in all this? >> kevin did serve some time in prison. and i -- i don't believe that diane would even want him to serve life in prison for her murder. but in my mind, he should still be behind bars. >> reporter: but now, kevin's got a second chance at life. he says he's dedicating it to his mother. >> she's looking down, and she sees that i'm maturing. and i am gonna be the man that she wanted me to be. >> reporter: so, in the end, what do we make of this mind-boggling whodunnit where no one can say for sure who murdered diane kyne? leaving a husband and son, still pointing the finger at each other, still professing love for diane but one of them still defiantly lying about having killed her. >> i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." >> it's like a bloody movie and it is. it's just so intense and so deep. you go through all of these range of emotions that you don't know, you know? that was the first time i started to care about my life. i could

what do we make of this mind-boggling whodunnit where no one can say for sure who murdered diane kyne? leaving a husband and son, still pointing the finger at each other, still professing love for diane but one of them still defiantly lying about having killed her. >> i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." >> it's like a bloody movie and it is. it's just so intense and so deep. you go through all of these range of emotions that you don't know, you know? that was the first time i started to care about my life. i could have been an entirely different person. >> it was a mind-boggling mystery for almost 20 years, and she was at the center. >> i'm john walsh. 1-year-old savanna lee barnett is missing from isle of palms, south carolina. >> a child who suddenly vanished. >> the most important thing in my life was taken from me. just instant horror of where is she? >> what had happened to baby savanna? the answer would come decades later and astonish the world. >> it happened so fast, i couldn't fathom what was going on. >> imagine, your mother a fugitive. y