Samuel Little might be serving a life sentence in a California prison, but 40 years ago, he said, he was in Tampa Bay killing again.

After his 2014 conviction for killing three California women between 1987 and 1989, Little confessed to a total of 93 murders last year. The FBI now says he is the most prolific killer in U.S. history.

FBI crime analysts believe all of his confessions, including two he claims happened in Tampa Bay, are credible. So far, 50 confessions have been verified with many more pending final confirmations.

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Little, 79, said he met a black woman in Clearwater around 1977 or 1978, then killed her in Plant City. He also claims to have killed a black woman in Tampa Bay in 1984.

“Apparently, Mr. Little has quite a bit to say, so as more details come, we’re looking to see if any details will tie him to anything specific here,” Tampa Police spokesman Steve Hegarty said. “We’re still talking to FBI but haven’t definitely linked him to any thing around that time period.”

Sketch of a woman Samuel Little claims to have killed in Plant City. [ FBI ]

Since first confessing to the killings last year, Little has drawn sketches of about 16 of his alleged victims, including the two in Tampa Bay and another seven from various Florida cities. Despite Little’s current life sentence and failing health, investigators still want to hold him accountable for as many crimes as they can.

Sketch of a woman Samuel Little claims to have killed somewhere in Tampa Bay. [ FBI ]

“For many years, Samuel Little believed he would not be caught because he thought no one was accounting for his victims,” FBI crime analyst Christie Palazzolo said in a news 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.”

According to the FBI, Little strangled 93 victims, mostly women, between 1970 and 2005. He avoided any convictions until 2014, but had numerous run-ins with the law throughout the country since the mid-60s. Many of his victims included prostitutes, drug addicts and others on the fringes of society.

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Born in Georgia in 1940, Little moved to Florida to live with his mother in the late ’70s where he said he worked in a cemetery and as an ambulance attendant before he began traveling around the country.

The FBI and law enforcement agencies encourage anyone with information on his unlinked confessions to contact law enforcement.

“I don’t know where this is headed,” Hegarty said, “but our detectives don’t want to miss an opportunity to close a case that might have been a missing person at the time or an unsolved murder.”

Tipsters can call 1-800-CALL-FBI or submit at tip online at tips.fbi.gov.