(CNN) Samuel Little, who claims to be the most prolific serial killer in American history, has admitted killing a woman 25 years ago in Pine Bluff, Arkansas, a Pine Bluff official tells CNN.

Terry Hopson said he investigated the death of 26-year-old Jolanda Jones in 1994 for the city police. He told CNN at the time it looked like an "unexplained death."

Hopson, who is now a deputy police chief with Pine Bluff, said he spoke to Texas officials over the phone about Little's confession to Jones' murder. He said he remembered the case clearly, and that police "fowarded the charge" to the county prosecutor's office.

Little, 79, claims he killed at least 90 people from 1970 to 2005, a Texas prosecutor said.

Little is serving three life sentences on California convictions and is cooperating with authorities from different states behind bars. Detectives have linked him to 60 deaths, Ector County, Texas, District Attorney Bobby Blanda told CNN last June.

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