i'm chris hansen.t was a mystery for more than a decade, a kind and gentle wife and mother killed. police had a suspect, but they also had a problem. the man they thought was behind the crime had an airtight alibi, he was at work at his job in a plant the very moment the killing took place. so, would there be justice? one woman was about to risk her own life to make sure of it. two women, mary dabbs and teresa french. they'd never met but became connected in a way no one could have predicted. was there a day went by that you didn't think about teresa? >> never. >> it would be terror in both their lives that would ultimately bring them together. one helping the other in a case that frustrated police for nearly 15 years. the story begins with teresa french, who was a young mother in muncie, indiana, back in 1993. >> she had an innocence about her. >> she just loved everybody. she was just so nice and friendly. >> would never say anything bad about anybody. >> teresa was beautiful and petite, had an open