U.S. Supreme Court Justice Samuel A. Alito Jr. stayed Missouri's planned execution late Tuesday after the U.S. 8th Court of Appeals had cleared the way for the lethal injection to proceed.
Russell Bucklew had been scheduled to die after midnight at a prison in Bonne Terre for the 1996 murder of Michael Sanders and the kidnapping and rape of the woman who lived with Sanders.
Bucklew would be the first inmate executed in the U.S. since the botched execution of Clayton Lockett in Oklahoma in April. Lockett's unexpectedly difficult death brought new scrutiny on laws - such as Missouri's - that allow state officials to hide information on where they get lethal-injection drugs.
Bucklew's attorneys have said that he suffers from a condition called cavernous hemangioma, which involves frequent bleeding and tumors in his face and neck.
One doctor who examined him reported that there was substantial risk to Bucklew of "suffering adverse events during the execution, including hemorrhaging, suffocating, and experiencing excruciating pain."
On Monday, a federal judge had denied Bucklew's appeal on medical grounds.
That decision was reversed by a panel of the U.S. 8th Circuit Court of Appeals in St. Louis, which voted 2 to 1 to grant Bucklew a stay of execution so that his medical condition could be reviewed.
Missouri officials disagreed and appealed for the case to be reheard by the full court of appeals. The full court lifted the stay. Of the 11 members of the appellate court participating, four voted to leave the stay of execution in place.