The information was provided in a timeline that Robert Patton, director of the department of corrections, sent to Gov. Mary Fallin. Patton said Lockett was supposed to be X-rayed Tuesday morning as part of the execution procedure and was tasered shortly before 6 a.m. when he refused to allow guards to put restraints on him to escort him to the medical unit.
The timeline also showed that because a good vein could not be found in Lockett's arms or legs, the intravenous line for the execution drugs was inserted in his groin.
Lockett was pronounced dead at 7:06 p.m., more than 40 minutes after midzolam, the first of three drugs, was administered. Patton had announced a halt to the execution 10 minutes earlier because the doctor present said Lockett had not gotten enough of the drugs to kill him.
The cause of death is believed to be a heart attack.
Patton in his report also said that at the medical unit staffers found an apparently self-inflicted wound on Lockett's arm that did not require stitches.
Lockett was sentenced to death for the 1999 murder of Stephanie Neiman, 19, of Perry, Okla. Neiman was buried alive after she became involved in a bungled home invasion while dropping a friend off.
Another inmate, Charles Warner, was scheduled to be executed at 8 p.m. Tuesday. That execution has now been stayed for at least two weeks.
Fallin announced Wednesday that the state will investigate what happened and determine if changes need to be made to execution protocols, promising the review will be independent. Dean Sanderford, Lockett's lawyer, said no investigation by the Oklahoma Department of Public Safety will be truly independent.
"In order to understand exactly what went wrong in last night’s horrific execution, and restore any confidence in the execution process, the death of Clayton Lockett must be investigated by a truly independent organization, not a state employee or agency," he said in an emailed statement.