PHOENIX — The U.S. Supreme Court has refused to clear the way for an Arizona death row inmate to be executed for killing a man more than 30 years ago during a robbery, denying the state's request to lift a lower-court's order that blocked the execution.

The late Tuesday decision by the nation's highest court postpones Wednesday's scheduled execution of 70-year-old Edward Schad, who was convicted of murdering 74-year-old Lorimer "Leroy" Grove of Bisbee in 1978.

The 9th Circuit Court of Appeals had blocked Schad's execution while a judge considers his claim that he was denied effective legal representation after his conviction. The state had asked the U.S. Supreme Court to let the execution go ahead as planned.

Schad's execution would be Arizona's 34th since 1992. Most recently, Richard Dale Stokley, convicted of murdering two 13-year-old girls in Cochise County in 1991, was put to death by lethal injection Dec. 5.

Grove was last seen leaving Bisbee in a Cadillac that was pulling a trailer on his way to visit his sister in Washington state. Eight days later, his body was found south of Prescott in underbrush off the shoulder of U.S. 89. A sash-like cord that had been used to strangle Grove was still knotted around his neck when the body was discovered.

Authorities say Schad drove Grove's car across the country for a month, used Grove's credit cards and forged a check from the victim's bank account. His lawyers say Schad has more than paid for his murder conviction in Grove's death and that no purpose would be served by his execution.