A murderer who would have become America's first executed inmate in months won a reprieve Thursday from the US Supreme Court a little more than an hour before he was scheduled to die by lethal injection. James Harvey Callahan, set to die at 6 p.m. CST (0000 GMT), was granted a stay, Holman prison warden Grantt Culliver told officers on death row. The Supreme Court's brief order did not detail why it granted the stay. It would have been the first US execution since September, when the high court agreed to consider whether lethal injection is cruel and unusual punishment. The inmate's attorney had asked the high court to halt the execution after a federal appeals court lifted a stay granted by a Montgomery judge. The Supreme Court on Sept. 25 agreed to hear a challenge filed by two Kentucky death row inmates over that state's lethal injection method. No US executions have taken place since then, except for one that occurred in Texas just hours after the decision was made.