The U.S. Supreme Court has turned down a long shot request to reconsider the appeal of an Alabama inmate scheduled to be executed by lethal injection next month.

Justices on Monday refused the rehearing request by Tommy Arthur, who has had seven execution dates postponed.

The court in November stayed Arthur's execution to consider whether to hear the appeal centered on a requirement that condemned inmates challenging their method of execution name a feasible alternate method. The court in February ruled it would not hear the case and maintained the decision.

Arthur is scheduled to be executed by lethal injection on May 25 for the 1982 slaying of Troy Wicker. He has a pending a civil suit against the state arguing Alabama is improperly secretive about its execution protocol.