Unknown Serial Killers of America, William Suff

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, a deranged killer stalks sex workers in Riverside, Calif., claiming the lives of 13 women.

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.

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.

When droves of young gay men disappear in Indiana in the '90s, an amateur sleuth uncovers clues that point to a likely killer.