>> he went under, and when he came up, he said he no longer saw his wife. >> he was just hysterical.s >> they were never able to find her. >> it was a heart-wrenching story. so why then were so many people so suspicious? >> no one knows exactly what happened on that boat. >> an accident? a disappearance? >> you thought would, she figured us? >> or maybe a murder? >> there's no way. absolutely no way. >> i felt like the police were just trying to frame an innocent man. >> now, she would be the one to unravel it all. >> i thought, i could do this. >> in a dangerous undercover operation. >> tell them everything.th >> what? >> my heartbeat was going so fast. i said, "you need to tell me the truth." >> welcome to "dateline." they were a good looking couple with an expanding family and a