What happens when a person confesses to so many murders that the FBI can't even find all the victims?

In the case of serial killer Samuel Little, he draws his victims from memory and the authorities publish those drawings in the hope someone recognizes them.

Little is 78 and was raised in Lorain, Ohio. He's been in prison since 2012. Prior to that, he traveled the country for more than three decades murdering women. He's confessed to 90.

He says he has killed in Cincinnati and Northern Kentucky, and the FBI recently released sketches of those alleged victims.

One of the haunting sketches shows a black woman with short style hair. Little says he killed this woman in Cincinnati in 1974. Scrawled next to the portrait: "Tall girl by highway by sign."

A second sketch shows a white woman with reddish hair and blue eyes. Little told the FBI he met this woman in Columbus, killed her and disposed of her body in Northern Kentucky in 1984.

When the FBI released the killer's list of victims, which he recited from memory. They had already confirmed 34 of them. Since November, eight more cases have been confirmed or matched to open cases.

Little was arrested at a Louisville homeless shelter in 2012. He was extradited to California on drug charges, and once there his DNA was quickly matched to three unsolved homicides in the 1980s. He was sentenced to life in prison.

This spring, Little wanted to move to a different prison. The FBI and other investigators had long suspected he had killed other people. In exchange for moving, Little started talking.

He confessed to 90 murders, investigators said, many of which he remembers in great detail.

His killings span the country from the east to the west coast with incidents in 16 states.

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The Ohio Attorney General's Office keeps comprehensive records of unsolved homicides in the state.

Two unsolved deaths from 1974 involved black females in the Cincinnati area, but neither death matches Little's profile.

Angela Tucker, age 5, was killed in a fire in Over-the-Rhine that was ruled an arson and 70-year-old Mattie Broadus was stabbed to death in a Downtown apartment.

But Little knocked out his victims and strangled them. They were often prostitutes or other vulnerable women.

"Many of these deaths were not classified as homicides but attributed to drug overdoses, accidents, or natural causes," the FBI said.

The Cincinnati Police Department said it is aware of Little's confession and is looking into deaths from that time.

Little is in poor health and will likely stay in prison in Texas until his death, investigators said.

"The goal now is to identify his victims and provide closure and justice in unsolved cases," the FBI said in a news release.

For more information or to report potential case links to Samuel Little, people can contact the FBI's violent crime apprehension program at 800-634-4097.