(CNN) — An Oklahoma inmate died Tuesday evening of an apparent heart attack after authorities botched the delivery of drugs and stopped his execution.
Another execution scheduled for the same day was postponed.
Convicted murderer Clayton Lockett was sedated and then given the second and third drugs in the protocol, Oklahoma Department of Corrections Director Robert Patton told reporters.
“There was some concern at that time that the drugs were not having the effect, so the doctor observed the line and determined that the line had blown,” he said.
“I notified the attorney general’s office, the governor’s office of my intent to stop the execution and requested a stay for 14 days for the second execution scheduled this afternoon,” said Patton, referring to the execution of Charles Warner.
Lockett later suffered what appeared to be a heart attack and died, the director said.
Gov. Mary Fallin issued an executive order granting a stay for Warner and ordered an investigation.
Lockett remained unconscious after the drugs were administered and died in the execution chamber at 7:06 p.m., according to her office.
“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 in a statement. “I have issued an executive order delaying the execution of Charles Frederick Warner for 14 days to allow for that review to be completed.”
The constitutionality of lethal injection drugs and drug cocktails has made headlines since last year, when European manufacturers — including Denmark-based Lundbeck, which manufactures pentobarbital — banned U.S. prisons from using their drugs in executions. Thirty-two states were left to find new drug protocols.
According to the Oklahoma Department of Corrections, its protocol includes midazolam, which causes unconsciousness, vecuronium bromide, which stops respiration, and potassium chloride, which is meant to stop the heart.
Lockett was convicted in 2000 of a bevy of crimes, including first-degree murder, first-degree rape, kidnapping and robbery in a 1999 home invasion and crime spree that left Stephanie Nieman dead and two people injured.
In 2003, Warner was convicted for the 1997 first-degree rape and murder of his then-girlfriend’s 11-month-old daughter, Adrianna Waller.
“Something went horribly awry,” Warner’s attorney told CNN late Tuesday.
“Oklahoma cannot carry out further executions until there’s transparency in this process,” said Madeline Cohen.
“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,” Gov. 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.”
Warner’s execution is scheduled for May 13. You can read more on our affiliate KFOR’s website, including a detailed timeline of events.
CNN’s Eliott C. McLaughlin and Ross Levitt contributed to this report.
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