The death row sentence for a man convicted of the 1984 murder of an elderly woman has been overturned after he was ruled mentally retarded.

Limestone County District Attorney Kristi Valls says Kenneth Glen Thomas will head to court May 27 to be re-sentenced to life in prison without parole. He has been on death row since his 1986 murder conviction.

Authorities say Thomas killed 82-year-old Flossie McLemore, his neighbor, and then tried to conceal the murder by setting McLemore's house on fire.

Valls says a judge ruled in an April 21 hearing that Thomas is not eligible for execution.

Valls says Alabama Attorney General Troy King had fought Thomas' claim that he is retarded.