A US death row inmate has writhed in agony and mumbled incoherently in a botched execution using untested drugs, before dying of a heart attack 40 minutes into the ordeal, news reports say.
The gruesome end to the life of Clayton Lockett, a convicted murderer and rapist, prompted allegations that what he underwent amounted to torture. It also caused the state of Oklahoma, where Lockett died, to postpone the scheduled execution of a second inmate.
Lockett was administered a new, untested three-drug protocol in what would have been the central state's first double execution in 80 years.
But Oklahoma Department of Corrections Director Robert Patton ordered the execution of Lockett stopped about three or four minutes after the start of the injection, citing a "vein failure," a prisons spokesman said.
Lockett died of a massive heart attack about 40 minutes later after receiving all three drugs, spokesman Jerry Massie said.
Even though he was administered the injection, "the drugs didn't go into the system," Massie said.
The drugs were a sedative, an anaesthetic and a lethal dose of potassium chloride.
Patton immediately ordered a 14-day delay for the execution of Charles Warner, who had been set to be executed two hours after Lockett.
"About 13 minutes into the execution, after he had been declared unconscious, the inmate began writhing in pain. His body was sort of bucking. He was clenching his jaw," Tulsa World editor Ziva Branstetter told MSNBC television.
"Several times he mumbled phrases that were unintelligible. Only word we could make out was: 'Man!' He seemed to be in a lot of pain.
"Several times he rose, his head and shoulders rose up off the gurney as if he was trying to get off the gurney."
Shortly thereafter, the prison warden closed the blinds, preventing reporters from witnessing what was going on in the execution chamber, Branstetter said.
"After weeks of Oklahoma refusing to disclose basic information about the drugs for tonight's lethal injection procedures, tonight, Clayton Lockett was tortured to death," Warner's lawyer Madeline Cohen said in a statement.
She called for an independent investigation and autopsy to learn what went wrong.
"The state must disclose complete information about the drugs, including their purity, efficacy, source and the results of any testing," Cohen added.
"Until much more is known about tonight's failed experiment of an execution, no execution can be permitted in Oklahoma."
The state had previously postponed the two executions in March because of a shortage of lethal injection drugs.
Lockett was convicted in 2000 for the rape and murder of a young woman he kidnapped, beat and buried alive.
Warner was convicted for the 1997 rape and murder of an 11-month-old girl.
Cohen had argued against the new injection combination, saying the "experimental new drug protocol, including a paralytic," would make it "impossible to know whether the executions will comport with the Eighth Amendment's ban on cruel and unusual suffering."
Both Lockett and Warner had argued they had the constitutional right to know the composition and origin of any drugs used in the lethal injection.
