In August of 2003, 19-year-old Kaysi McLeod had a fight with her mother, ran out of their Colorado home, and took off down the road on her bicycle. At first, her divorced parents, Rob and Lori, didn't worry too much - Kaysi had run away before. And... (more), like many teens, she had a rebellious streak and was once involved in drugs. But Kaysi had also recently put her life back together, so when she didn't show up for work a few days later, panic set in. Lori's new boyfriend, Scott Kimball worked for the FBI, and assured everyone he could help find her, but weeks, then months, then finally years passed, without a trace. That story was eerily familiar to two other fathers, Bob Marcum and Howard Emry. Their daughters, 25-year-old Jennifer Marcum and 24-year-old LeAnn Emry, had also gone missing from the Denver area in 2003. LeAnn's car had been abandoned in Utah, Jennifer's had been left at the Denver airport. Yet, when each father went to the authorities for help, they were turned away. And since no one was investigating, none of the three families learned about each other's plight for years. The twists and turns in the three maddening cases would be the ultimate test of the families' love and determination. The cases would also challenge the intelligence and skill of two investigators - one, a local cop, the other, a seasoned FBI agent - who were brought together by chance to unlock the mystery. Along the way, a menacing killer with the chilling nickname of "Hannibal" would be revealed. His identity would shock everyone - most of all the FBI - and ultimately be the key to solving the cases and bringing justice to three heartbroken families. Harold Dow reports on "48 Hours Mystery: "Hannibal Unmasked".