GALVESTON, Texas (AP) — A man already sentenced to death for an Oklahoma cold-case killing has pleaded guilty to murder in the deaths of two girls and a young woman whose disappearances also went unsolved for decades.

William Reece pleaded guilty Wednesday in a courtroom in Galveston and nearby Angleton in the 1997 killings of 12-year-old Laura Smither of Friendswood, 17-year-old Jessica Cain of Tiki Island and 20-year-old Kelli Cox of Denton.

The 62-year-old was serving a 60-year prison sentence for a 1998 Texas kidnapping in 2016 when he began cooperating with investigations of the other deaths.

He was sentenced to death last year for the 1997 killing of 19-year-old Tiffany Johnson of Oklahoma City.