>> this woman knew him all too well. i >> started snooping and i found everything. >> this reporter made some unnerving discoveries, to. >> he scared a lot of people. he swindled a lot of people. >> the story of his dirty deeds riveted the nation in a hit podcast. >> this is "dirty john". >> but dirty was about to turn dark. >> he's got duct tape, he's got all the tools ready to kidnap her. >> will this mom and her daughters learn the truth in time? >> she was in a panic. she said, i saw john outside in a car. >> a story ending in savagely that would stun even a police. >> there's no way he gets away with this. unless he killed her. >> hello, and welcome to "dateline". after string of failed relationships, debra newell thought she had finally found her mr. wright. john meehan seems mark,