This special edition of A&T examines the growing phenomenon of teenage killers. First... A missing 13-year-old boy was last seen with his best friend. This friend was eventually proved to be his killer, but seemingly had no motive. Then...A young girl disappeared on Halloween. Her killer sent riddles to the police daring them to catch him. Lastly... Two parents were found beaten to death in their home, their younger daughter missing. She was found with a band of teenagers - a vampire cult - who admitted to the murders. The daughter was exonerated in her parents' deaths.