Tuesday night’s botched execution in Oklahoma, which resulted in an inmate’s writhing death from a heart attack 43 minutes after he received what was supposed to be a lethal injection, was just one in a series of bungled execution attempts the past few years. It’s prompting calls for a moratorium on capital punishment from death penalty opponents.

The inmate, Clayton Lockett, was confirmed unconscious 10 minutes after the first dose in the state’s new three-drug protocol was administered. The first drug, midazolam, is intended to render a person unconscious. But three minutes later, he began breathing heavily, thrashing and straining to lift his head, media witnesses said.

Reporters for Tulsa World and KFOR-TV in Oklahoma City said Lockett called out from the gurney, “man.”

The blinds were then lowered to prevent people in the viewing gallery from seeing inside the death chamber. Oklahoma Department of Corrections Director Robert Patton answered a ringing phone and left the room with a few officials.

Patton told reporters Lockett’s vein line had “blown.” When asked what he meant, Patton said the vein had “exploded.”

Soon afterward, an alarmed Oklahoma Gov. Mary Fallin stayed for 14 days the other execution that was scheduled for Tuesday night, the Associated Press reported.

“I have asked the Department of Corrections to conduct a full review of Oklahoma’s execution procedures to determine what happened and why during this evening’s execution of Clayton Derrell Lockett,” Fallin said. “I have issued an executive order delaying the execution of Charles Frederick Warner for 14 days to allow for that review to be completed.”

Ryan Kiesel, executive director of the American Civil Liberties Union of Oklahoma, also called for an investigation as well as an immediate moratorium on all executions in the state, saying, “In Oklahoma’s haste to conduct a science experiment on two men behind a veil of secrecy, our state has disgraced itself before the nation and world.”

And National Coalition to Abolish the Death Penalty responded in a statement: “This night will be a catalyst for those aggrieved and outraged to continue to fight to abolish the death penalty in Oklahoma and every other state in America.”

Executions have become increasingly difficult for states to carry out over the past two years because of similar incidents. Licensed physicians are now unwilling to have anything to do with them on ethical grounds. Pharmaceutical companies that market the most tested drugs have cut off supplies, forcing states to obtain compounds they refuse to describe from suppliers they refuse to identify.

These controversies have begun a whole new phase in the decades-long struggle over capital punishment. For years, opponents of the death penalty fought about its fundamental fairness under the Constitution. When they lost that fight, they attacked the capacity of the criminal justice system to actually mete out the death penalty reliably and without racial bias. They lost that fight, too, in the 1980s.

Now the battle concerns not who dies, but how they die, and the competence of states to carry out executions humanely.

The visibility and drama of Oklahoma’s trouble Tuesday night is likely to intensify that conflict, though, there has been no doubt about the guilt of these two condemned men. Lockett, 38, was convicted of shooting a teenager and watching as she was buried alive. Warner, 46, was convicted of raping and murdering his girlfriend’s 11-month-old baby.

Both were set to be executed Tuesday, Lockett at 6 p.m. Central time and Warner at 8 p.m.

Lockett’s execution was halted when it appeared the lethal injection administered to him was ineffective. Contrary to the description from media eyewitnesses, officials said he remained unconscious and passed away in the execution chamber at 7:06 p.m.

“There was some concern at that time that the drugs were not having that [desired] effect, and the doctor observed the line at that time and determined the line had blown,” Patton said in a news conference. “After conferring with the warden, and unknown how much drugs went into him, it was my decision at that time to stop the execution.”

Still, 43 minutes after the first injection, Lockett suffered a heart attack and died.

Tulsa World enterprise editor Ziva Branstetter, who one of 12 media witnesses, wrote a dramatic account of the execution:

6:28 p.m. Fifty milligrams of midazolam have been injected into each of Lockett’s arms to start the process, an attempt to sedate him before the second and third drugs are administered to stop the breathing and the heart.  Lockett has spent the past several minutes blinking and occasionally pursing his lips.

6:29 p.m. Lockett’s eyes are closed and his mouth is open slightly.

6:31 p.m. The doctor checks Lockett’s pupils and places his hand on the inmate’s chest, shaking him slightly. ‘Mr. Lockett is not unconscious,’ Trammell states.

6:33 p.m. The doctor checks Lockett a second time after a full minute without movement. ‘Mr. Lockett is unconscious,’ Trammell states. It seems like it took longer than expected for this to occur. In past executions I have attended, there has been no notice that the inmate was unconscious, just a pronouncement of death after about eight minutes without much reaction from the inmate.

6:36 p.m. Lockett kicks his right leg and his head rolls to the side. He mumbles something we can’t understand.

6:37 p.m. The inmate’s body starts writhing and bucking and it looks like he’s trying to get up. Both arms are strapped down and several straps secure his body to the gurney. He utters another unintelligible statement. Defense Attorney Dean Sanderford is quietly crying in the observation area.

6:38 p.m. Lockett is grimacing, grunting and lifting his head and shoulders entirely up from the gurney. He begins rolling his head from side to side. He again mumbles something we can’t understand, except for the word ‘man.’ He lifts his head and shoulders off the gurney several times, as if he’s trying to sit up. He appears to be in pain.

6:39 p.m. The physician walks around to Lockett’s right arm, lifts up the sheet and says something to Trammell. ‘We’re going to lower the blinds temporarily,’ she says. The blinds are lowered and we can’t see what is happening. Reporters exchange shocked glances. Nothing like this has happened at an execution any of us has witnessed since 1990, when the state resumed executions using lethal injection.

6:40 p.m. A black landline phone rings in the viewing chamber and Patton leaves to take the call, stretching the phone cord out into the hall and closing the door behind him. Though the clock on the wall in the execution chamber is no longer visible, it seems like several minutes pass before Thompson is summoned out to the hallway.

Approximately 6:50 p.m. Patton comes back to the viewing room and says the execution has been ‘stopped. We’ve had a vein failure in which the chemicals did not make it into the offender. … Under my authority, we are issuing a stay for the second execution.’  The announcement is stunning and leaves us wondering what has happened to Lockett.

The court fight preceding the attempted executions had also been messy.

Lockett and Warner had sued the state for refusing to disclose details about the execution drugs, saying it violated the Constitution’s guarantee against cruel and unusual punishment. They argued that without knowing who manufactures the execution drugs, they had no way of ensuring the drugs would work as intended.

The case placed Oklahoma’s two highest courts at odds and prompted calls for the impeachment of state Supreme Court justices after the court last week issued a rare stay of execution. The high court later dissolved its stay and dismissed the inmates’ claim that they were entitled to know the source of the lethal drugs, the AP reported.

By then, Gov. Fallin had issued a stay of execution of her own — a one-week delay in Lockett’s execution that resulted in both inmates being set to die the same day.

After Tuesday’s failure, Lockett’s attorney David Autry questioned the amount of the sedative, midazolam, that was injected, saying he thought the 100 milligrams called for in the Oklahoma’s execution protocol was “an overdose quantity.” He said he was also skeptical of the department’s determination that Lockett’s vein had failed.

Tuesday was the first time the state had administered midazolam as the first drug in its execution protocol.

Earlier this year, the state attorney general’s office announced that a deal to obtain pentobarbital and vecuronium bromide, a muscle relaxer, had fallen through, and Lockett and Warner’s executions were delayed.

The new protocol was identified in court papers and included the combination of midazolam and hydromorphone.

Ohio inmate Dennis McGuire was the first U.S. inmate to receive this controversial combination earlier this year — and it reportedly caused him to make gasping-like sounds for several minutes before he was ultimately pronounced dead.

Regarding Warner’s scheduled execution, federal public defender Madeline Cohen, one of his attorneys, told the Washington Post, “Oh, we will be pursuing further action.”