A convicted double-murderer was due to be executed by lethal injection in Arizona on Wednesday after his defense team failed in its legal bid to force the state to disclose greater details about how he will be put to death.
Joseph Wood, 55, is one of six death row inmates who sued Arizona last month arguing that secrecy surrounding the drugs used in botched executions in Ohio and Oklahoma violated their constitutional rights.
On Saturday, the 9th US Circuit Court of Appeals put his execution on hold, saying Wood could suffer irreparable harm" unless the state divulged information about the drugs and the qualifications of the medical staff conducting the execution.
But on Tuesday, the US Supreme Court sided with the Arizona attorney general and lifted the stay of execution.
Wood's execution was set for 10 a.m. (1700 GMT) in the state prison in Florence, about 60 miles (100 km) southeast of Phoenix. The others who brought the legal suit remain on death row.
Two problematic executions this year renewed controversy over capital punishment and the way it is carried out.
In January, convicted rapist and murderer Dennis McGuire, 53, was put to death in Ohio, using a sedative-painkiller mix of midazolam and hydromorphone, the first such combination administered for a lethal injection in the United States. The execution took about 25 minutes to complete, with McGuire reportedly convulsing and gasping for breath.
In Oklahoma in April, convicted killer Clayton Lockett writhed in pain and a needle became dislodged during his lethal injection at a state prison. The execution was halted, but Lockett died about 30 minutes later of a heart attack.
Arizona, which has executed 36 people since reinstating the death penalty in 1992, says it will also use midazolam and hydromorphone, but in higher doses than in Ohio.
Arizona's last execution took place in October 2013 when Robert Glen Jones Jr., 43, was put to death for murdering six people during two robberies in Tucson in 1996.
Twenty-five people have been put to death nationwide this year, according to the Death Penalty Information Center.