It was like watching a clip from a “horror movie,” witnesses said, after new details emerged about the execution of Clayton Lockett -- who was sentenced to death on April 29 for the brutal 1999 murder of Stephanie Neiman. Instead of the normal 10 minutes, it took Lockett 43 minutes to die after an untested lethal cocktail was injected into his veins, the Agence France Presse wrote.

"The documents paint a picture of chaos in the execution chamber," Cary Aspinwall from Tulsa World, who reviewed the documents, said, according to CNN. "The execution team didn't have the size needles they needed, they couldn't find veins that would work and the drugs didn't start taking effect when they thought they would.”

More than 100 witnesses were interviewed for Department of Public Safety after the incident. The 5,000-page transcript was released after The Tulsa World filed a lawsuit against state police, the AFP wrote.

The first of three drugs, midazolam, was administered into his body via the femoral artery, but instead of pumping through his veins and leading to a quick death, the drug leaked into his body tissue and caused a “bloody mess.”

The paramedic, whose name hasn’t been revealed, failed multiple times to find a suitable vein, which even lead Lockett to say at one point, “I've got a vein in my leg -- in my right leg,” CNN wrote. But she didn’t want to use that vein “because they cause a lot of clots." Lockett responded, “Does it really matter?”

He was declared dead an hour after he was brought to the execution chamber. Lockett had no last words but his last moments might have been full of agony, the Washington Post wrote in 2014. “He looked like he was in pain to me,” a witness said at the time. “How much pain, nobody knows but him.”

Lawyers will argue the case to the Supreme Court on April 29, precisely one year after Lockett’s botched execution.

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