Federal appeals court halts mentally disabled Ga. man's execution

Updated 7:57 PM ET

(CBS/AP) JACKSON, Ga. - A federal appeals court halted the execution Tuesday of a Georgia man who killed a fellow prisoner in 1990, granting a last-minute stay to the inmate who defense attorneys argued was mentally disabled.

The 11th U.S. Circuit Court of Appeals issued the ruling for Warren Lee Hill as corrections officials prepared his lethal injection for later in the evening.

Earlier, Hill said the state Board of Pardons and Paroles has denied him clemency. Hill was scheduled to die by lethal injection at 7 p.m. According to the New York Times, Hill has an IQ of 70.

"We are greatly relieved that the Eleventh Circuit Court of Appeals has stayed the execution of Warren Hill, a person with mental retardation. All the doctors who have examined Mr. Hill are unanimous in their diagnosis of mental retardation," defense attorney Brian Kammer said in an email.

Hill's lawyers argue that he is mentally disabled and therefore shouldn't be executed. The state maintains that the defense failed to meet its burden of proving beyond a reasonable doubt that Hill is mentally disabled.

In a split decision, the Supreme Court of Georgia on Tuesday denied a stay of execution for Hill.

Hill was serving a life sentence when he was convicted in the 1990 death of a fellow inmate.