OKLAHOMA CITY (AP) — The head of Oklahoma’s Department of Corrections told Gov. Mary Fallin on Thursday that he needs more oversight of execution procedures and said it took officials 51 minutes to find a suitable vein before the botched execution earlier this week.

Clayton Lockett died of an apparent heart attack 10 minutes after prisons director Robert Patton halted the execution. The prisons chief said Lockett had an intravenous tap placed at his groin because suitable veins couldn’t be found elsewhere. That vein collapsed, and Patton said Lockett didn’t have another vein that was suitable — and that the state didn’t have another dose of the drugs available anyway.

The IV line was covered by a sheet because it had been placed at Lockett’s groin, Patton said in his letter to the governor. Its becoming dislodged wasn’t discovered until 21 minutes after the execution began and all of the execution drugs had been injected into the line.

“The drugs had either absorbed into tissue, leaked out or both,” Patton wrote. “The director asked the following question, ‘Have enough drugs been administered to cause death?’ The doctor responded, ‘No.’

After the doctor attending the execution found a faint heartbeat, Patton ordered the execution stopped. Lockett died anyway.

Madeline Cohen, an attorney for an inmate who had been scheduled to be executed two hours after Lockett, said Oklahoma was revealing information about the events “in a chaotic manner.”

“As the Oklahoma Department of Corrections dribbles out piecemeal information about Clayton Lockett’s botched execution, they have revealed that Mr. Lockett was killed using an invasive and painful method — an IV line in his groin,” Cohen said in a statement. “Placing such a femoral IV line requires highly specialized medical training and expertise.”

The second execution set for Tuesday night, of inmate Charles Warner, was initially rescheduled for May 13. Patton on Thursday called for an indefinite stay. Cohen said she agreed that an indefinite stay was necessary.

In recommendations to the governor, Patton also said it was wrong to leave “all responsibility and decision-making” to the warden of the Oklahoma State Penitentiary at McAlester, where executions are carried out.

“Those decisions should rest on upper management and ultimately on the Director of Corrections,” Patton wrote in a four-page letter detailing Lockett’s last day. He shared the letter at a Board of Corrections meeting Thursday.

The director said the state should:

• Conduct a full review of execution procedures, and he said he intended to contact other states to ensure Oklahoma “adopts proven standards.”

• Give Warner an indefinite stay rather than the two-week reprieve Gov. Mary Fallin gave him after Lockett’s botched execution. Once new protocols are written, Patton said, “staff will require extensive training.”

• Allow an external review of what went wrong at Lockett’s execution. “While I have complete confidence in the abilities of my Inspector General and his staff, I believe the report will be perceived as more credible if conducted by an external entity,” Patton said.

Fallin had announced similar steps Wednesday, including asking another member of her cabinet to review Corrections Department procedures.

“We look forward to a thorough review and a rewrite of the protocols for the state of Oklahoma in carrying out executions,” Patton said after the letter was released. “I do not know how long that investigation will take.

There is no timeline for the review, nor is there a timeline for the rewrite of the protocols. There is an active warrant in two weeks for an execution. I do not know if that will be completed by that time.”

He refused to answer additional questions about the execution.

Lockett’s execution Tuesday was to have started at 6 p.m., but a phlebotomist couldn’t find a suitable place for an intravenous line on Lockett’s arms, legs, feet and neck. Ultimately, he placed an IV line at Lockett’s groin and covered the area with a sheet, the letter said. A timeline released by Patton notes the phlebotomist working from 5:27 p.m. to 6:18 p.m.

The execution started at 6:23 p.m. but by 6:44 p.m., Lockett hadn’t died. Typically inmates die in about 10 minutes.

According to the timeline accompanying Patton’s letter to Fallin, a doctor attending the execution said that, after a vein collapsed, Lockett did not absorb a fatal dose of three execution drugs and the state didn’t have enough on hand to try again.

Patton stopped the execution at 6:56 p.m., but 10 minutes later Lockett apparently suffered a massive heart attack. Autopsy results are pending.

SEAN MURPHY, Associated Press