Imagine the monster terrorizing your town is the man who raised you. This is how it happened. Keith Hunter Jesperson, the Happy Face Killer, left notes taunting police, but his undoing was his own daughter. Melissa Moore noticed chilling patterns in her father's behavior. Understanding his serial killer psychology, she submitted a tip that caught him, leading to his 1995 confessions. What confirmed her worst fears? And if you want to go deeper, watch the BTK confession right now.