back to dateline welcome back to dateline, after the mysterious death of his wife catherine, paul novakng to move on. he relocated to florida, and had a new girlfriend. but then came that knock on the door and detectives placed paul under arrest. soon, he would learn that someone was claiming they had disturbing new details about the night of the fire. paul's world was about to turn upside down. once again, here's andrea canning with secrets and lies. >> katherine novak's death had been a cold case for more than three years. went out of nowhere a witness came forward. pointing a finger at catherine's estranged husband, paul. so, who was this mystery witness? a woman from paul's past? his ex girlfriend, michelle. >> michelle, who was the defendants alibi in 2008, has now come forward and said paul was not home. and that paul went to narrows burke, and paul killed katherine. >> what was that phone call like? >> it was now time to get to work. >> this man was the district attorney. he teamed up with the former da, steve. >> didn't feel good that you had a break? >> it's a break, again be w