An official report released Thursday finds that Oklahoma prison staff attempting to execute inmate Clayton Lockett in April failed to realize that lethal drugs were not going directly into his vein, leading to a botched execution and gruesome death that stirred a national debate over capital punishment.
Prison officials initially concluded that Lockett died of a heart attack, but an autopsy conducted in connection with the probe ordered by Oklahoma Gov. Mary Fallin found that he died from the lethal drugs.
At one point during the ordeal, Lockett appeared to struggle against his restraints. He was pronounced dead 43 minutes after the execution began even though the execution had officially been halted.
Lockett's was the first of two executions scheduled for April 29. The second was postponed after Fallin ordered the investigation into the case.
The report notes that the prison staff appeared to be under considerable stress because of the back-to-back executions.
One recommendation from investigators is to wait at least seven days between executions. Another is that a governor be notified if it takes longer than an hour to place an IV, raising the possibility that a postponement might be requested.
The results of the investigation, released by the Oklahoma Department of Public Safety, finds that a paramedic and doctor on duty during the event had tried 10 times for more than 50 minutes to secure an IV needle into a vein for the flow of drugs.
When they finally thought they had succeeded at securing an entry point in Lockett's groin, after cutting open his clothing, prison warden Anita Trammell directed that a sheet be placed over the prisoner to hide his genitals from view.
Investigators said the sheet prevented medical personnel from seeing that the drugs were piling up under his skin and not flowing properly into the vein. The problem created a swollen area larger than a golf ball, the report, that could not be seen because of the sheet.
A timeline in the report says Fallin's office told Corrections Department Director Robert Patton to proceed with the lethal injection after it became clear only one viable IV had been placed.
It was not until Lockett began to raise his head and make sounds -- some said he was mouthing words -- that officials realized there was a problem.
Dale Baich, a lawyer representing inmates on Oklahoma's death row, said the investigation report "raises more questions than it answers. The report does not address accountability."
The inmates filed a federal lawsuit in June alleging that the Oklahoma Department of Corrections was conducting cruel and unusual punishment with its lethal injection procedures.
Oklahoma officials administered three drugs in succession to execute Lockett, at least one for the first time. The first was midazolam, an anti-seizure medication used as an anesthetic followed by vecuronium bromide to paralyze Lockett and then potassium chloride to stop his heart.
The state obtained the drugs from an unnamed compounding pharmacy, a step that death penalty opponents say doesn't allow for quality control of the pharmaceuticals, because compounding pharmacies are only lightly regulated.
State investigators did not find any deficiency with the drugs Oklahoma obtained from the pharmacy.
Their report published Thursday said witnesses inside the chamber gave differing accounts of what happened after drugs were administered.
"The movement descriptions ranged from quivering to thrashing, but most agreed Lockett's head did rise off the table," the report says. "There were differing recollections regarding whether Lockett's eyes opened after he was deemed unconscious. The sound descriptions varied from mumbling to Lockett making statements. "
Sixteen minutes into the execution, blinds were lowered to shield the death chamber from the audience witnessing the execution. Members of the news media were escorted from the chamber.
The report describes the confusion that followed as officials stopped the execution and struggled with what to do next. Meanwhile, the drugs seeping into Lockett's body began to gradually kill him, the report says.
Investigators described how that early on the morning of his execution date, Lockett refused to leave his cell to undergo an examination. Guards saw blood and used a Taser to move the prisoner out of the cell.
They found he had cut his arms with a razor blade kept hidden in the cell, and he was treated for the wounds.
Lockett was sentenced to death for the 1999 murder of 19-year-old Stephanie Neiman who, with a companion, had stumbled upon Lockett and two accomplices during a home invasion in Perry, Okla.
Lockett shot Neiman twice and ordered his cohorts to bury her alive. The three then repeatedly sexually assaulted Neiman's companion.
Contributing: Doug Stanglin and the Associated Press