there's no way bill kyne would be convicted. t, but the defense would be "kevin did it." >> who is kevin kyne? who is this guy? >> kevin kyne is a name on paper. that man is not a kyne. and he is not my family. >> so where's justice 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 movi