On a hot summer night, 16-year-old Susana Morales was visitingher friend's house when she seemingly disappeared. A trackingapp on Susana's phone showed her walking home, then suddenlygoing the opposite direction in a car. Minutes later, herphone registered a crash alert, yet there were no signs of anaccident and no signs of Susana at the location. Afterreporting her missing, Susana's family took matters into theirown hands, retracing her steps and uncovering surveillancevideo just minutes before she vanished. In a heart-poundinginvestigation, explosive video tracks detectives — in realtime — as they hunt for clues in Susana's disappearance. Sixmonths later, a critical breakthrough led authorities toSusana and to a piece of evidence that broke the case wideopen. ABC News correspondent John Quiñones speaks to Susana'smother and reports on the shocking discovery that uncoveredsomeone no one had anticipated.