State Attorney General Gentner Drummond on Monday filed a petition with the U.S. Supreme Court in support of granting a stay of execution for death row inmate Richard Glossip.

Glossip, a former hotel manager, was found guilty of orchestrating the 1997 murder of his boss, Barry Alan Van Treese, 54, at the Best Budget Inn in Oklahoma City.

Glossip is set to be put to death by lethal injection on May 18 at the Oklahoma State Penitentiary in McAlester.

On April 26, the state Pardon and Parole Board split 2-2 on a clemency vote, meaning Glossip, 60, didn’t receive the majority support needed under Oklahoma law for Gov. Kevin Stitt to consider clemency.

More: Oklahoma Pardon and Parole Board denies clemency for death row inmate Richard Glossip

One member, Richard Smothermon, recused himself from the hearing because his spouse is a prosecutor who was involved in Glossip’s case.

Glossip asked the U.S. Supreme Court for a stay of execution. His attorneys cited Drummond's support for halting Glossip's execution.

Drummond, as well as Glossip’s attorneys, have attempted to cast doubt on Glossip’s trial and retrial, saying the state withheld some evidence from his defense team, and that a key witness was unreliable due to his drug addiction and struggles with mental health.

Indeed, Glossip has maintained his innocence.

He was found guilty and sentenced to death for paying Justin Sneed, a 19-year-old accomplice and maintenance man, to kill Van Treese.

Sneed beat Van Treese to death with a baseball bat and was sentenced to life without parole after testifying that Glossip hired him for the murder.

He said Glossip pressured him into doing it and offered him $10,000 as payment. He testified against Glossip at two trials.

Glossip maintains that Sneed actually killed the motel owner during a botched robbery for drug money.

More: Court rejects AG's request to overturn Glossip's murder conviction; execution date set

Glossip claims Sneed incriminated him to avoid getting the death penalty, and that Sneed, a meth addict, made admissions in jail and later in prison about framing Glossip, and also has talked of recanting his testimony.

By live video during his clemency hearing, Glossip pleaded with the board to recommend clemency.

“I’m not a murderer and I don’t deserve to die for this,” Glossip said.

District attorneys from across the state, including former Oklahoma County District Attorney David Prater, attended the hearing to support the Van Treese family and oppose Drummond, who previously said he was unaware of any former state attorney general supporting a clemency application for a death row inmate.

In a letter to the board, Drummond wrote he believes that Glossip is guilty of accessory after the fact. Although he may be guilty of first-degree murder, the record does not support that he is guilty of first-degree murder beyond a reasonable doubt, Drummond wrote.

Glossip’s case has garnered national attention, including from some celebrities calling for clemency, as well as a bipartisan group of Oklahoma lawmakers. But he has lost court cases since his conviction.

More: Oklahoma attorney general asks for clemency for death row inmate

In 2013, the 10th U.S. Circuit Court of Appeals ruled that Glossip had received “a fundamentally fair” trial in 2004.

In 2014, the state Pardon and Parole Board unanimously denied Glossip’s request for clemency.

In 2015, officials called off Glossip's execution when a doctor realized the wrong heart-stopping drug had been delivered.

The state Court of Criminal Appeals rejected two previous challenges to Glossip’s conviction in November.

In April, the court ruled 5-0 that Glossip is not entitled to relief.

Of Sneed, the key witness, Judge David Lewis wrote:

"His testimony was not clearly false. Sneed was more than likely in denial of his mental health disorders, but counsel did not inquire further."

In his petition to the U.S. Supreme Court, Drummond wrote that Glossip intends to promptly file a petition seeking a review of the decision.

“The state intends to acquiesce in that petition,” Drummond wrote. “Consequently, the state supports Glossip’s request to stay his execution, which is currently scheduled for May 18, 2023.”

During an emotional plea with the Pardon and Parole Board, Van Treese family members called on the panel to deny Glossip clemency.

Derek Van Treese, a son, told the board two juries found Glossip guilty and recommended the death penalty.

“I’ve spent half my life waiting for justice to be served for those responsible,” he said.

This article originally appeared on Oklahoman: Oklahoma AG files petition supporting stay of execution for Glossip