LINCOLN, Neb. (AP) — A man who was convicted of three separate killings has died at the Nebraska State Penitentiary in Lincoln.

82-year-old Clarence Victor suffered from a long-term medical condition. He died in the prison’s nursing facility at around 11 a.m. Tuesday.

Victor had been imprisoned since 1988. He’d been convicted of first-degree murder and sentenced to death for killing 82-year-old Alyce Singleton in her Omaha home in 1987.

In 2000 the Nebraska Supreme Court upheld a judge who resentenced Victor to life in prison under a law barring the execution of mentally disabled inmates. The judge accepted tests showing Victor had an IQ of 65.

Victor was convicted of manslaughter in 1964 and second-degree murder in 1976.