Unknown Serial Killers of America

Chilling confessions from a vicious slasher detail only some of his 100+ victims; when he's set to be the first serial killer ever released from prison, an eyewitness from decades prior could force justice on the man who vows to kill again.

In the '90s, aderanged killer stalks sex workers in Riverside, Calif., claiming the lives of 13 women; when a would-be victim describes the perp to police, the race is on to catch the murderous john before he strikes again.

Five corpses are found on the Florida hog trails; the investigation stalls until two men narrowly escape the perp's clutches; years later, eight more bodies are found in nearby woods, leaving police to wonder if it's the same evil killer.

Multiple unidentified bodies are found inside barrels in a New Hampshire forest; decades later, a murder 3,000 miles away reveals their connection to a serial predator who targets women and children, and changes his identity after every violent kill.

When the bodies of 12 Black women surface in Missouri and Illinois, the serial killer taunts authorities by sending a cryptic letter to the local paper; as disturbing video evidence emerges, the scope of his crimes is uncovered.

When droves of young gay men disappear in Indiana in the '90s, an amateur sleuth uncovers clues that point to a likely killer; with little physical evidence, the case stalls until a mind-boggling 10,000 bones are unearthed in a family's backyard.