An Oklahoma inmate who recently lost a legal battle to find out exactly which drugs would be used to kill him died of a heart attack tonight after the state botched his execution.

Convicted murderers Clayton Lockett and Charles Warner were both scheduled to be executed tonight after losing an appeal to force the state to disclose the source of its new, secret lethal injection drug combination.

Lockett, who was convicted of kidnapping, beating, raping, shooting, and burying alive a 19-year-old woman, was scheduled to go first and received the injection at 6:23 pm. Warner, convicted of raping and killing an 11-month-old baby, was to follow at 8 pm.

But things went terribly wrong.

The New York Times rather passively points out that "It did not appear that any of the drugs themselves failed, but rather the method of administration," and even after a doctor declared him to be unconscious, witnesses say Lockett was awake and yelled "man" and "something's wrong."

Doctors pulled the curtain after he apparently tried to rise up off the table.

Lockett officially died of a heart attack at 7:06 pm. In the meantime, Warner's execution has been stayed for at least 14 days.

According to Mother Jones, Oklahoma quietly procured the experimental cocktail after drug manufacturers stopped producing sodium thiopental, the lethal injection drug of choice, citing moral grounds. [The "black comedy of increasingly desperate attempts" by states to procure execution drugs is also detailed in this December New Yorker piece.]

Both men received a brief stay of execution earlier this year when they sued the state, arguing they were entitled to know the source of the lethal injection drugs that Oklahoma had been secretly preparing.

After the governor challenged the State Supreme Court's ruling for a delay and the legislature started to discuss impeaching the justices, the Oklahoma Supreme Court denied the request, writing:

"The plaintiffs have no more right to the information they requested than if they were being executed in the electric chair, they would have no right to know whether OG&E or PSO were providing the electricity; if they were being hanged, they would have no right to know whether it be cotton or nylon rope; or if they were being executed by firing squad, they would have no right to know whether it be by Winchester or Remington ammunition."

Department of Corrections officials apparently proposed two combinations of different drugs for the executions tonight before deciding on a cocktail of three chemicals—midazolam for anxiety, vecuronium bromide to relax the muscles, and potassium chloride to stop the heart. According to the Times, that combination has been used before in Florida, but with a "much higher dose" of midazolam because the other two drugs are known to cause "agonizing suffocation and pain."

UPDATE 10:25 PM: Oklahoma Governor Mary Fallon has ordered a "full review of Oklahoma's execution procedures."

[Image of Clayton Lockett, left, and Charles Warner via AP]