For 43 agonizing minutes this past April, Oklahoma inmate Clayton Lockett writhed and seethed in his execution chair. The lethal injection drugs coursing through his bloodstream were meant to make the process quick and painless. But 10 minutes after Lockett’s struggle ended, at the behest of the Department of Corrections director, he suffered a heart attack and died.

A new autopsy report claims the cause of Lockett’s death was, in fact, the cocktail of lethal injection drugs and not the heart attack, as many had deduced. The medical examiner who inspected Lockett’s body found all three drugs still in his system, declaring the cause of death “judicial execution by lethal injection." Lockett’s death was the second in a string of three failed executions, after one in January and preceding another in June.

Some argue the autopsy report raises more questions than it answers. Dale Baich of the Federal Public Defender's Office in Phoenix, who represents a group of Oklahoma death row prisoners who commissioned an independent autopsy report, says the 43 minutes of writhing isn’t easily explained away by the drugs’ presence. "What this initial autopsy report does not appear to answer," Baich said, according to The Associated Press, “is what went wrong during Mr. Lockett's execution.”

It may be the case the lethal injection drugs were the root cause of death, but their presence in his bloodstream doesn’t cancel out the chance his heart attack was caused by those drugs. Officials at the Oklahoma State Penitentiary in McAlester, for instance, acknowledge Lockett’s vein collapsed at one point during the injection process. Follow-up investigations revealed the medical technicians poked him 12 times trying to find a vein. Eventually, they settled on one in his groin.

In response to Lockett’s gruesome procedure, Gov. Mary Fallin ordered public safety officials to retrace their steps to figure out what went wrong. A large camp argues it’s the drugs themselves. For as long as lethal injection has been the go-to method, technicians have used the same three-pronged approach, with the drug sodium thiopental being the key component. In 2011, the United States’ sole supplier of sodium thiopental, Hospira, cut its ties to pursue new business overseas. The move left the U.S. without a trusted drug. And the supposed frontrunner, midazolam, has failed in its last three uses — each time causing the inmate to produce audible and breathless gasps.

Given the severity and high-profile nature of Lockett’s case, the state Court of Criminal Appeals agreed to not schedule any executions until November, as the investigation proceeds. "We suspect they are in the final stages of that process," said Alex Weintz, a spokesman for Fallin, in a statement. In addition, Weintz said, Fallin “has asked DPS [Department of Public Safety] to make recommendations on what possible updates to the protocols we can pursue."

Some states have already jumped the shark on lethal injection altogether. This past May, for instance, Tennessee made headlines when it plugged its electric chairs back in. Gov. Bill Haslam signed a law that allowed the chair’s use, but only after lethal injection had been ruled out due to lack of available drugs. New Hampshire and Washington are the only two states to allow death by hanging, in New Hampshire at the decision of the Corrections officials and in Washington at the request of the prisoner.

Though the autopsy report doesn’t specify which protocols could help smooth out the execution process, past research suggests sloppy injections could be a culprit. In 2005, a study was published revealing 43 of the 49 executions that were tested did not meet the minimum surgical dosage of anesthesia. This wasn’t an accident: “Executioners had no anesthesia training, drugs were administered remotely with no monitoring for anesthesia, data were not recorded and no peer-review was done,” the researchers wrote.

The inmates may as well have been executing each other.