More than eight months after a chaotic, botched execution in Oklahoma that drew intense criticism, triggered an investigation and prompted a revamped lethal injection procedure, the state resumed executions on Thursday.

The first inmate executed under the new policy was Charles Warner, who was put to death at the state penitentiary in McAlester after the U.S. Supreme Court denied his request for a stay. Gov. Mary Fallin (R) confirmed the execution Thursday night.

Warner did not show any obvious signs of distress, media witnesses reported. But after the first drug was administered, he said, “My body is on fire,” according to the Associated Press.

“Justice was served tonight as the state executed Charles Warner for the heinous crime of raping and murdering an infant,” Fallin said in a statement.

Warner, who was convicted of raping and murdering an 11-month-old, was originally supposed to be executed the same night as the high-profile execution of Clayton Lockett last year. But it was postponed — first for two weeks, then for much longer — after Lockett kicked, bucked his body and grimaced during his execution.

That execution was one of three that went awry last year, bringing increased attention to problems facing the dwindling number of states that execute inmates. A drug shortage stemming from European companies and officials objecting to the death penalty has caused states across the country to turn to new, largely untested combinations to execute inmates rather than using the three-drug combination that was typical until 2010. Lethal injection remains the primary method of execution in the country, but as the shortage has persisted, some states have discussed returning to older methods like firing squads.

Lockett, who had been convicted of murder and other charges, ultimately died 43 minutes after the procedure began. As accounts of his writhing and grimacing spread, disapproval poured in from death penalty opponents as well as President Obama and the United Nations. Gov. Mary Fallin (R) ordered a review, and Robert Patton, head of the state’s Department of Corrections, asked that executions be postponed until the state could figure out its new execution protocol.

state investigation later determined that the execution team failed to properly place the intravenous needle to deliver the lethal injection drugs to Lockett. The review also found that there were problems with this team’s training and the way they handled the execution as well as the confusion that reigned after it became clear the execution was going awry. This investigation also found that the cramped scheduling — two executions set just two hours apart — created additional stress and urgency for some of the people involved.

Attorneys for Charles Warner asked the Supreme Court to delay his execution and three others scheduled to occur by early March. The Supreme Court on Thursday night denied the stay, with four of the justices dissenting from the decision. Justice Sonioa Sotomayor authored a dissent saying that while she agrees that the four inmates asking for stays should be punished for their crimes, “the Eighth Amendment guarantees that no one should be subjected to an execution that causes searing, unnecessary pain before death.”

In the filings, Warner’s attorneys argued against executing inmates with the drug midazolam, a sedative used to sedate surgery patients before anesthesia. They had similarly asked the U.S. Court of Appeals for the 10th Circuit to delay his execution, but the appeals court denied the request earlier this week.

Midazolam cropped up in three problematic executions last year. It was used during Lockett’s lethal injection and in an Arizona execution that lasted for nearly two hours as the inmate gasped and snorted before dying. Ohio said last week that it would no longer use midazolam, a decision it announced almost a year after the state used the drug in an execution that lasted for nearly 25 minutes as the inmate appeared to gasp and choke.

Oklahoma was using midazolam as part of a three-drug combination for the first time during Lockett’s execution last year. The state’s new lethal injection policy, which went into effect in September, includes a much higher dose of midazolam. When Lockett was executed, 100 milligrams of the sedative were supposed to be injected; the state now says it will use 500 milligrams of midazolam, the same amount used by Florida in its executions.

Sotomayor, writing in her dissent, said she questioned a lower court’s determination that midazolam would “work as intended difficult to accept given recent experience with the use of this drug.” Since a paralytic is also injected as part of the lethal injection, that “may mask the ineffectiveness of midazolam as an anesthetic,” because an inmate could be conscious but unable to move, she wrote.

“The questions before us are especially important now, given states’ increasing reliance on new and scientifically untested methods of execution,” Sotomayor said.

Florida, which has used midazolam in executions since 2013, also carried out n execution Thursday evening. The state executed Johnny Kormondy, who was convicted of killing a banker and raping his wife in 1993.

His attorneys had asked the U.S. Supreme Court to stay his execution, but the full court denied the request on Wednesday. The court also denied a second request made Thursday that asked them to delay it until they had made a decision about Warner’s request.

“Prison officials used midazolam on Charles Warner, a drug that had failed during Lockett’s execution and that doctors say has no place in lethal injection,” Cassandra Stubbs, director of the American Civil Liberties Union’s Capital Punishment Project, said in a statement Thursday night.”Due to the paralyzing effects of other drugs Warner received tonight, we will never know whether he experienced excruciating pain throughout the execution.”

Before he was executed, Warner apologized to his family for the pain he caused them. “I’m not a monster,” he said, according to the Associated Press. “I didn’t do everything they said I did.”

Use of the death penalty continued to decline last year, as the 35 executions carried out was the lowest number in two decades, and fewer people were sentenced to death, according to the Death Penalty Information Center. Fewer states were executing inmates, with just three states — Florida, Texas and Missouri — carrying out four out of five executions in 2014. While public support for the death penalty has declined since the mid-1990s, a majority of Americans still support the death penalty, something that did not change much after the high-profile issues last year.

If botched executions continue to occur, it could have an impact on how the public feels about the death penalty, according to Deborah W. Denno, a law professor at Fordham University. “It’s not going to be one execution or one incident,” she said after the Arizona botch. “It’s going to be the conglomeration of incidences that’s going to make an impact.”

In Oklahoma, the new lethal injection policy also states that five journalists would be able to view executions going forward, down from the 12 media witnesses that had been allowed previously. News organizations had filed a lawsuit in the summer arguing for greater media access to Oklahoma’s executions, arguing that key parts of Lockett’s execution and his death were not visible to those in attendance.

[This post has been updated. First published: 3:58 p.m.]