The botched execution of a death row inmate in the US in which a new drug combination was being used for the first time is expected to intensify the debate over how lethal injections are handled.
Clayton Lockett writhed, clenched his teeth and appeared to struggle against restraints holding him to a gurney before Oklahoma prison officials halted the execution. He later died of a heart attack.
The 38-year-old was declared unconscious 10 minutes after the first of three drugs in the new lethal injection combination was administered yesterday evening. Three minutes later, he began breathing heavily, writhing, clenching his teeth and straining to lift his head.
Officials later blamed a ruptured vein for the problems, which are likely to fuel debate about the ability of states to administer lethal injections that meet the US Constitution's requirement they be neither cruel nor unusual punishment.
The blinds were eventually lowered to prevent those in the viewing gallery from watching, and the state's top prison official eventually called a halt to the proceedings. Lockett died a short time later, the Department of Corrections said.
"It was a horrible thing to witness. This was totally botched," said Lockett's lawyer, David Autry.
A four-time felon, Lockett was convicted of shooting 19-year-old Stephanie Neiman and watching as two accomplices buried her alive in rural Kay County in 1999. She and a friend had interrupted the men as they robbed a home.
Questions about execution procedures have drawn renewed attention in recent months, as several states scrambled to find new sources of drugs because manufacturers that oppose capital punishment, many based in Europe, have stopped selling to US prisons and corrections departments.
In Ohio, the January execution of an inmate who made snorting and gasping sounds led to a civil rights lawsuit by his family and calls for a moratorium. The state stood by it but said on Monday that it is boosting the dosages of its lethal injection drugs.
Defence lawyers have unsuccessfully challenged several states' policies of shielding the identities of the source of their drugs. Missouri and Texas, like Oklahoma, have both refused to reveal their sources and both have carried out executions with new supplies.
The Lockett execution was the first time Oklahoma had used a particular sedative as the first element in its drug combination. Other states have used it before - Florida administers it as part of its three-drug combination. Oklahoma used much less than Florida does.
"They should have anticipated possible problems with an untried execution protocol," Mr Autry said. "Obviously the whole thing was gummed up and botched from beginning to end. Halting the execution obviously did Lockett no good."
Republican governor Mary Fallin has ordered a 14-day stay of execution for an inmate who was scheduled to die two hours after Lockett, Charles Warner. She ordered the state's Department of Corrections to conduct a "full review of Oklahoma's execution procedures to determine what happened and why during this evening's execution".
Robert Patton, the department's director, halted Lockett's execution about 20 minutes after the first drug was administered. He later said there had been vein failure.
Once an inmate is declared unconscious, the state's execution protocol calls for the second drug, a paralytic, to be administered. The third drug stops the heart.
Mr Patton said the second and third drugs were being administered when a problem was noticed. He said it is unclear how much of the drugs made it into the inmate's system.
Lockett began writhing at 6:36pm local time and at 6:39pm a doctor lifted the sheet covering him to examine the injection site.
"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," Mr Patton said at a news conference afterwards, referring to Lockett's vein rupturing.
After an official lowered the blinds, Mr Patton made a series of phone calls before calling a halt to the execution. "After conferring with the warden, and unknown how much drugs went into him, it was my decision at that time to stop the execution," he said.
Mr Autry was immediately sceptical of the department's determination that the issue was limited to a problem with Lockett's vein.
He said: "I'm not a medical professional, but Mr Lockett was not someone who had compromised veins. He was in very good shape. He had large arms and very prominent veins."
The American Civil Liberties Union of Oklahoma, a human rights group which was not a party in the legal challenge to the state's execution law, called for an immediate moratorium on state executions.
Executive director Ryan Kiesel said: "This evening we saw what happens when we allow the government to act in secret at its most powerful moment and the consequences of trading due process for political posturing."
Warner had been scheduled to be executed two hours later in the same room and on the same gurney. The 46-year-old was convicted of raping and killing his roommate's 11-month-old daughter in 1997. He has maintained his innocence.
Lockett and Warner had sued the state for refusing to disclose details about the execution drugs, including where Oklahoma obtained them.
The case, filed as a civil matter, 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 drugs. By then, Ms Fallin had issued a stay - a one-week delay in Lockett's execution that resulted in both men being scheduled to die on the same day.