“Nightline” co-anchor Juju Chang reports on the notorious “Happy Face Killer,” who went on a killing spree throughout the United States in the 1990s, and the recent identification of one of his “Jane Doe” victims, Patsy Skiple. This episode showcases news-making “20/20” interviews about the case, which ABC News has been following for over a decade, and features new interviews with Skiple’s family members, the police lieutenant who spearheaded the DNA investigation into identifying Skiple’s remains, and Melissa Moore, the daughter of the Happy Face Killer.