(CNN) Samuel Little, the California inmate who claims to be one of the most prolific serial killers in US history, has been linked to 60 deaths, a Texas prosecutor said Friday.

Ector County District Attorney Bobby Bland said investigators have confirmed Little is connected to deaths in 14 states.

Little claims to have killed people between 1970 and 2005 in 14 states from Florida to California. Authorities had previously confirmed he was linked to 34 killings.

Samuel Little has confessed to at least 90 killings.

Little, 79, is in a California state prison, according to corrections department spokeswoman Vicky Waters. He is serving life sentences for three murders.

He has been cooperating with investigators from different states and is in bad health, Bland said. In November, Little was charged in Ector County for a 1994 killing.

Read More