A convicted mass killer from the 1970s is again scheduled for execution Tuesday after an appeals court lifted a last-minute stay that was based on his mental illness. His attorneys sought a last-minute reprieve from the U.S. Supreme Court.

The execution of John Ferguson, 64, was tentatively back on for 6 p.m. at Florida State Prison pending a final order from the governor's office, state corrections officials said. Ferguson has been on Florida's death row for 34 years.

The 11th U.S. Circuit Court of Appeals on Monday lifted a stay put in place over the weekend by a judge in Florida. Ferguson's lawyers argued he is mentally ill and therefore the Constitution prohibits the state from executing him.

His attorneys sought reinstatement of the stay in an emergency filing Tuesday morning with the U.S. Supreme Court. There was no immediate ruling from the justices.

Ferguson was convicted of killing eight people in South Florida in 1977 and 1978, including a teenage couple.

Two of the three appeals court judges in Atlanta ruled that U.S. Judge Daniel Hurley "abused" his discretion on Saturday when he issued a stay in the case.