The justices took up Glossip's appeal of a lower court's refusal to grant him a hearing after that court determined the newly obtained evidence would not have changed the outcome of Glossip's case. The Supreme Court in May 2023 halted Glossip's scheduled execution while they considered whether to take up his appeal challenging his conviction on various grounds.

Glossip was convicted of commissioning the 1997 murder of Barry Van Treese, owner of the Best Budget Inn motel in Oklahoma City where Glossip was a manager. Van Treese was beaten to death with a baseball bat by maintenance worker Justin Sneed, who confessed to the killing and said Glossip had hired him to do it.

Recent investigations into the case led Glossip's lawyers to evidence that they said cast doubt on the reliability of Sneed, the prosecution's key witness, prompting them to seek relief at the Oklahoma Court of Criminal.

Defense lawyers in two separate filings told the Oklahoma appellate court that Sneed had misled the jury about his psychiatric condition at the time of the murder, and that prosecutors failed to disclose that Sneed had considered recanting his incriminating testimony against Glossip.

The Oklahoma Court of Criminal Appeals in November 2022 and again in April 2023 ruled against Glossip, based in part on that court's determination that the evidence would not have made a difference to jurors, and denied Glossip's request for a hearing.

His legal team responded by filing a pair of appeals to the Supreme Court, one of which was supported by Oklahoma's Republican Attorney General Gentner Drummond, with the justices then halting his execution that had been scheduled for May 18, 2023.

Glossip was found guilty of first-degree murder in 1998. After an appeals court threw out that conviction, he was found guilty again in 2004. He has drawn a range of prominent supporters while pursuing long-running appeals of his conviction, including from celebrity Kim Kardashian.

The Supreme Court in 2015 ruled against a bid by Glossip and two other death row inmates to challenge Oklahoma's lethal injection protocol, with the justices deciding that the state's execution method did not violate the U.S. Constitution's ban on cruel and unusual punishment.

The case is due to be argued before the Supreme Court during its next term, which begins in October.

(Reporting by John Kruzel; Editing by Will Dunham)

By John Kruzel