with grief. it was a tragedy. but for lisa's dead, a sheriff's deputy it was no mystery. he was sure he skbu where the killer was. a neighbor with a gun and a grudge. >> i thought they better get there before i do. >> some said the couple was having trouble. that seth has secret. >> did she tell you she sent topless pictures? >> someone said it's right under cops' noses. a case unfolding on camera, one nat would stes three jures, shatter two families. and chase one final twist. >> that was her biggest secret. ♪