Updated — April 29, 11:30 p.m. ET:
An Oklahoma inmate died Tuesday night of a heart attack after the botched delivery of a new lethal drug combination, Oklahoma Department of Corrections Director Robert Patton said.
The execution officially began at 6:23 p.m. CT when officials administered the first drug. A doctor declared Lockett to be unconscious at 6:33 p.m. CT, then officials proceeded to inject the other two drugs into the inmate.
A few minutes later, Lockett, 38, reportedly started moving on the gurney and eventually started shaking uncontrollably. Witnesses reported hearing someone say "something's wrong," although it was not clear who made the statement.
A doctor reportedly lifted the sheet that was covering Lockett to examine the injection site and an official who was inside the death chamber lowered the blinds.
"It's come to my attention, I'm stopping the execution," Patton said to the media in the execution chamber. "We've had a vein failure, in which the chemicals did not make it into the offender."
Lockett died at 7:06 p.m. CT of a heart attack with all three drugs having been administered.
Charles Warner's execution was also set for Tuesday night, but the action was stayed for 14 days after the botched injections.
Lockett, a four-time felon, was convicted of shooting 19-year-old Stephanie Neiman in 1999 and watching as accomplices buried her alive. Warner, 46, was convicted of raping and killing an 11-month-old girl in 1997.
The drug mix set to be used in Lockett's and Warner's executions had never been tried before by the state of Oklahoma, Jerry Massie, public information officer for the state department of corrections, said.
Lockett was first to be injected with midazolam, a benzodiazepine meant to make the inmate unconscious and unable to feel pain. The second injection is of vecuronium bromide, meant to stop breathing, and then potassium chloride, which stops the heart.
The combination has been used previously in Florida, but with a higher dose of the first drug than was used Tuesday in Oklahoma. Without effective sedation, the prisoner may suffer from suffocation and pain.
Drug companies say they do not want their information released because they are fearful of political repercussions and even physical attack, and often refuse to supply drugs, forcing states to scramble to find new sources and try untested combinations.
Others argue not releasing where the drugs come from violates due process and the ban on cruel and unusual punishment, because it is not clear if the drugs are safe and effective. Both inmates had tried to delay the executions citing the secrecy behind where the state acquired the drugs.
God blessed us with our precious daughter, Stephanie for 19 years. Stephanie loved children.She worked in Vacation Bible School and always helped with our Church nativity scenes. She was the joy of our life. We are thankful this day has finally arrived and justice will finally be served.Susie and Steve Neiman, 4-29-14
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. I have issued an executive order delaying the execution of Charles Frederick Warner for 14 days to allow for that review to be completed.
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. Without question, we must get complete answers about what went wrong. There must be an independent investigation conducted by a third-party entity, not the Department of Corrections. We also need an autopsy by an independent pathologist and full transparency about the results of its findings. Additionally, the state must disclose complete information about the drugs, including their purity, efficacy, source and the results of any testing. Until much more is known about tonight's failed experiment of an execution, no execution can be permitted in Oklahoma.
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. The greatest power any government has over an individual is to take that person's life. More than any other power, the exercise of the power to kill must be accompanied by due process and transparency. 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. This is not about whether these two men are guilty; that is not in dispute. Rather, it comes down to whether we trust the government enough to allow it to kill its citizens, even guilty ones, in a secret process.