after the mysterious death of his wife catherine, paul novak was trying to move on. 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 & lies." >> reporter: catherine novak's death had been a cold case for more than three years when, 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 la france, who was the defendant's alibi in 2008, has now come forward and said paul was not home and that paul went to narrowsburg and that paul killed catherine. >> what was that phone call like? >> it was now time to get to work. >> reporter: jim farrell was now the district attorney. he teamed up with the former d.a., steve lungen. >> didn't it feel good you had a break?