A medic had so much trouble inserting an IV during a botched Oklahoma execution that the inmate volunteered he might have a better vein on his right leg. The injection team ultimately decided to run the line through a vein in Clayton Lockett's groin — even though they didn't have a needle of the right size.

Those are some of the details in newly released documents about the April 29 lethal injection that sparked a federal review of execution protocols nationwide. The Tulsa World newspaper sued to get the material, which includes transcripts of interviews conducted by investigators after the debacle.

Investigators had previously determined that Lockett was not fully sedated and woke up midway through the procedure because the IV line was improperly placed, allowing the lethal chemicals to seep into tissues instead of his vein. The new documents provide more detail about how it happened.

The unidentified paramedic said that when he arrived at the prison for the first of two executions that night — using the sedative midazolam in a three-drug cocktail for the first time — the atmosphere was unusual.

"There was an air of urgency there. The 'quick quick, got to get it done, got to get it done and got to make sure that everything is done right,'" he said.

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But right from the start, things went wrong. Lockett, he said, had dehydrated himself and, as a former intravenous crystal meth user, did not have many good veins. The medic managed to insert one needle, but didn't have any tape with him, so the needle came loose.

A doctor tried to access the jugular vein but could not. They then tried to go through the collarbone and failed there, too. Lockett, who kidnapped and buried alive a 19-year-old, offered an alternative.

"He said, 'I've got a vein in my leg, my right leg,'" the medic recalled. "And I said, 'Well, I don’t like to do those because they cause a lot of clots.' He said, 'Does it really matter?'"

The decision was made to put the IV into Lockett's femoral vein through his groin. The medic said a 2.5 inch needle was required but they only had needles that were 1.25 inches.

"Well, we'll just have to make it work," the doctor said, according to the medic.

He said it wasn't clear until the second drug — a paralytic — was being pumped in that it wasn't working.

"One of the executioners said, 'He's trying to get up off the table' and I thought, 'What?'" the medic said.

"The warden was very upset," the medic added. "Nobody wants a prisoner in an execution situation to suffer."

The execution was halted but Lockett died anyway. Lethal injections were put on hold while the state police conducted an investigation, but resumed earlier this year with the execution of Charles Warner — the man who was supposed to die after Lockett that night.

Charles Warner, left and Clayton Lockett, right. Oklahoma Department of Corrections / AP file

Although the U.S. Supreme Court declined to stop Warner's execution, the justices have since agreed to hear a challenge by Oklahoma death row inmates to the state's use of midazolam. Arguments in that case are scheduled for next month.

Oklahoma turned to midazolam after it ran out of the execution drugs it used to rely on — because manufacturers won't sell them for the purpose of killing someone.

The Tulsa World reported that there was so much secrecy surrounding the effort to find new drugs that Corrections Director Robert Patton didn't know the state had found a pharmacist to provide them until he saw a news report about it.