The FBI says it is now confident that Samuel Little is the most prolific serial killer in American history—and the number of confirmed murders could still rise by more than 40. The 79-year-old, who started cooperating with law enforcement last year, has confessed to murdering 93 women across America between 1970 and 2005, NBC reports. The FBI says its Violent Criminal Apprehension Program—ViCAP—has now verified 50 of those killings and is working with authorities to confirm more. Gary Ridgway, the "Green River Killer," was convicted of 49 murders, though authorities suspect there could have been 20 more. Little was already serving three life sentences for murder in California when he confessed to the other 90 killings.
Authorities say Little, a former boxer who grew up in Ohio, managed to evade detection for so long because he lived a transient lifestyle and tended to prey on sex workers, drug users, and others whose deaths were often not seriously investigated—or even recorded as murders, the AP reports. Most of the victims were strangled. "For many years, Samuel Little believed he would not be caught because he thought no one was accounting for his victims," ViCAP analyst Christie Palazzolo said in an FBI press release. "Even though he is already in prison, the FBI believes it is important to seek justice for each victim—to close every case possible." The FBI release includes details of some of the murders investigators are still trying to confirm and chilling video of some of Little's confessions. (Read more Samuel Little stories.)