Oklahoma’s ability to carry out executions according to its own laws is even more suspect than it originally seemed. According to a report in The Oklahoman, a man named Charles Warner was killed in January using potassium acetate—the same incorrect drug that led to the postponement of Richard Glossip’s death last week.

An autopsy report for Warner obtained by the newspaper shows that he was executed with a cocktail of drugs that included potassium acetate instead of potassium chloride, the final chemical in Oklahoma’s standard lethal injection protocol. According to the state medical examiner’s autopsy report, the syringes used to inject Warner were labeled potassium chloride, but the vials used to fill them were labeled potassium acetate.(The Oklahoman’s article is behind a paywall but the Associated Press has a summary here.)

Last week, Oklahoma Governor Mary Fallin issued a final-hour stay on the execution of Richard Glossip, a man many believe may be innocent, because the state’s department of correction received a shipment of potassium acetate instead of potassium chloride. Scott Pruitt, the state’s attorney general, subsequently halted all executions in the state pending an investigation of the botched shipment.

Warner was the first person in the U.S. ever to be executed by potassium acetate, according to the Death Penalty Information Center. According to reports, he said “my body is on fire,” after receiving the first drug, a sedative called midazolam, but did not show any subsequent distress. He was killed in 18 minutes.

Like Glossip, Warner once received a stay on his execution due to DOC incompetence. It was initially scheduled to take place in 2014, but it was postponed after officials missed the vein of a man named Clayton Lockett when inserting an IV line. Lockett’s death took 45 minutes, during which time he woke up, moaning and writhing in pain.

Fallin acknowledged to the Oklahoman that potassium acetate may have been used in Warner’s death, claiming that she was not aware of that possibility until the shipment that was slated to kill Glossip.

Image via Oklahoma Department of Corrections. Contact the author at andy@gawker.com.