>> reporter: his kids says they did not hear him leaving the house and there was no evidence that dave was at the crime scene. >> did you find any dna? >> no. >> reporter: hairs? anything? >> but then they just begun to uncover the troubling secrets of dave and debbie hawk. coming up, a family divided. >> my suspicion was growing stronger and stronger. when the "disappearance of debbie hawk" continues. e of ♪