22. The Original Night Stalker

In the 1980s, a serial killer prowled the posh streets of Orange County. Police were unaware of the serial attacks until 1996, when DNA revealed the killer's secret and they linked four murders to a single DNA profile. Detectives uncovered three more crimes attributed to the man dubbed "The Original Night Stalker" before learning he had an earlier career as a serial rapist! Watch as cold case detectives compare the attacker's DNA with nearly every convicted violent offender in California.