But it was a mystery as to when the prison decided to use potassium acetate in the first place — and why no one in charge appeared to know about the change until the very last minute. Oklahoma has never used the drug in executions, nor is it known to be an appropriate substitute for potassium chloride — the third in Oklahoma’s official three-drug protocol. Indeed, on Wednesday the DOC provided documents to reporters that listed the formula for Glossip’s execution as made up of three drugs: midazolam, which sedates the prisoner, followed by rocuronium bromide (which causes paralysis and stops breathing) and finally potassium chloride (to stop his heart).

In the media room on the grounds of the Oklahoma State Penitentiary, Department of Corrections Director Robert Patton told a throng of bewildered reporters that it was actually his office that requested the stay, in order to give the state time to do its “due diligence” and “review” the protocol.

The stay was in part so unexpected because Glossip’s appeals on grounds of innocence had been repeatedly rejected. Glossip was condemned to die for the January 1997 murder of Oklahoma City motel owner Barry VanTreese based almost entirely on the word of his confessed killer, a 19-year-old meth addict and drifter named Justin Sneed. Sneed implicated Glossip as the mastermind behind his crime, and testified against him in order to avoid the death penalty. In exchange, he is serving a life sentence in a medium security state prison. (For full background on the case, read The Intercept’s July investigation .)

The stay came just before 4 p.m., almost an hour after the U.S. Supreme Court declined to intervene in the case, and as witnesses were waiting to be taken to the death chamber.

I N A DRAMATIC and wholly unexpected move, Oklahoma Gov. Mary Fallin halted the execution of Richard Glossip on Wednesday, citing “last-minute questions” about the lethal injection protocol the state planned to use to kill him. In a brief statement, Fallin — who has previously denied clemency to Glossip — announced her decision to issue a 37-day stay of execution in order to determine if one of the drugs the state intended to use, potassium acetate, is actually “compliant” with the state’s “court-approved execution procedures.”

Director Patton did not take questions. So it remains unclear how potassium acetate came to replace potassium chloride, or when the governor was informed. But the change appeared particularly brazen given the recent scrutiny of Oklahoma’s lethal injection process. Glossip first earned national attention as the named plaintiff in, the Supreme Court case that forced a national debate about midazolam, a benzodiazepine used as a substitute for sodium thiopental — a barbiturate used for decades as the first in the three-drug protocol — and linked to a number of botched executions.

Although potassium chloride and potassium acetate are part of the same family of drugs, the latter is described as having a variety of applications, including as a food additive, a runway de-icer, and use in mummification. There is no track record for its use in executions, nor is it clear what would constitute a fatal dose. One pharmacologist, David Kroll, estimated in an article for Forbes that, at least in rodents, it would take 20 percent more of the drug to have the fatal effects of potassium chloride.

The last-minute swap raises more questions about Oklahoma’s capacity to competently carry out executions — a concern that has plagued the state since its horribly botched execution of Clayton Lockett in 2014. In that case, Lockett writhed on the gurney for nearly an hour after a paramedic and physician tried clumsily to insert an IV line into his body. He eventually died of a heart attack.

Glossip’s execution was supposed to be the first following the Supreme Court’s June upholding of Oklahoma’s protocol. Since then, the DOC has remodeled its death chamber, reportedly procuring a new execution deathbed and new equipment, including an ultrasound machine, to ensure IV lines are fitted properly. The renovation also happened to diminish the transparency of the process: The state eliminated from its viewing area seven seats previously available for media witnesses, reducing the total number of journalists’ slots from 12 to five, while also removing the clock from the execution chamber. Now corrections officials will provide details on the time it takes the state to kill a prisoner.

T HE TURN OF EVENTS on Wednesday was particularly dramatic outside the prison, where more than a dozen members of Glossip’s family had gathered. Some wore T-shirts with his picture on the front and, on the back, “PLEASE HELP ME FREE AN INNOCENT MAN.” Everyone believed the execution was imminent, if not underway. But anguish turned to relief and jubilation once someone saw a tweet from a journalist inside the prison. “Stay! Stay!” the person screamed.

Don Knight and Dale Baich, defense attorneys who have handled different aspects of the case, were themselves unaware of the stay until they heard the cries of celebration. Later, Baich, who was part of the legal team that challenged Oklahoma’s use of midazolam before the Supreme Court earlier this year, released a statement: “Today’s hastily abandoned plans show what happens when states carry out executions in secrecy with unqualified execution team members and no public oversight.”

“I literally thought I was fixin’ to lose my best friend,” said Mark Smith, Glossip’s nephew, who told The Intercept that he has driven from Clayton, Oklahoma, to visit his uncle every weekend for the last two years. Smith said he grew up fishing and having cookouts with Glossip, whom he described as generous and an important influence on him. “That man kept me out of trouble and kept my mind straight,” he said. “He’s not a murderer.”

For Billie Jo Boyiddle, Glossip’s niece, it was the fourth time she had experienced the fear of an execution date. “People are listening now — but the people who need to listen won’t,” she said. She was already in tears when she arrived at the prison, along with her husband and two of her sons, the youngest of whom is 12; an erroneous Facebook post had reported that the Supreme Court had denied a stay, long before it actually did. “It’s just devastating.”

Melissa Johnson, a resident of McAlester, Oklahoma — where executions are carried out — was also outside the prison with her 19-year-old son and his girlfriend. She heard about the case only two weeks ago, after Glossip received his last stay. Knowing that the execution was supposed to take place in her own backyard was “nauseating,” she said. She is not affiliated with any anti-death penalty organizations, she said, “I’m just a Christian.”

Sister Helen Prejean, who has spearheaded the campaign to save Glossip’s life, was elated that the stay had been issued: “A food preservative!” she exclaimed after learning about the state’s drug quandary. “And a Richard preservative.”

The last time a stay was granted, by the Court of Criminal Appeals, Glossip’s family celebrated by going back to Boyiddle’s home, where they released colorful balloons. They arrived at the prison today with balloons in their truck, which they passed around. Following news of the stay, Boyiddle’s husband, Mike Campbell, tearfully led the group in a prayer, thanking God, as well as Gov. Fallin. He also blessed Glossip — “Ricky” — and said, “I know God, Lord, that you answered our prayers and you’re going to continue to hold up this family, you will continue to hold up this case, and will continue to help us fight the death penalty across this world — not just in Oklahoma, but everywhere.”

The family then released their balloons, which floated up above the scarred white brick walls of the prison.

Glossip’s next execution date is Friday, November 6.

Caption: The niece of Richard Glossip, Billie Jo Boyiddle, hugs Mike Campbell after hearing about the stay of execution outside the Oklahoma State Penitentiary, in McAlester, Oklahoma, Sept. 30, 2015.