Oklahoma Attorney General Scott Pruitt said he was assigning investigators from his office to help with the review.
Before the execution, Pruitt disputed contentions that drugs for the lethal injection were experimental.
Tuesday was the first time Oklahoma used midazolam, a sedative, as the first element in its execution drug combination. There has been difficulty in getting execution drugs as some pharmaceutical companies have refused to provide them to states to conduct lethal injections.
“Those drugs to be used in the executions of Lockett and Warner — midazolam, vecuronium bromide and potassium chloride — have been used by other states at other times in the lethal injection process,” Pruitt said.
Oklahoma was using 100 milligrams of midazolam, while Florida uses five times as much. Pruitt said medical testimony indicates 50 milligrams of the drug was sufficient for patients undergoing neurosurgery.
The Corrections Department will not release any medical details about Lockett’s execution until an autopsy and investigation are complete, said spokesman Jerry Massie.
Oklahoma law requires that all executions be accomplished through lethal injection unless this method is found unconstitutional, in which case executions could be done by electrocution, and if that was found unconstitutional, a firing squad could be used. The law could be changed through legislation.
Rep. Aaron Stiles, R-Norman, chairman of the House Judiciary Committee, said the panel may now look into giving the Corrections Department more options in conducting executions, including the possibility of using a firing squad or the electric chair.
“This has raised enough issues that we should definitely look at not only giving the Department of Correction more options, but maybe giving the defendant options,” Stiles said. “We could say ‘Here are your three choices. Choose which one you think is the best.’
“It would be difficult to complain if he chooses the option.”
Background on cases
A four-time felon, Lockett was convicted of shooting 19-year-old Stephanie Neiman and watching as two accomplices buried her alive in rural Kay County in 1999. Neiman and a friend had interrupted the men as they robbed a home.
Warner had been scheduled to be executed two hours later, in what would have been the first time the state held two executions in one day since 1937. The 46-year-old was convicted of raping and killing his live-in girlfriend's 11-month-old daughter in 1997.
Lockett and Warner had sued the state for refusing to disclose details about the execution drugs, including where Oklahoma obtained them. The case, filed as a civil matter, placed at odds the state’s two highest courts, the Oklahoma Supreme Court and the Oklahoma Court of Criminal Appeals.
The state Supreme Court initially granted a temporary stay of execution and then dismissed the stay. Before the dismissal, the governor said the court exceeded its authority and some Oklahoma legislators called for impeachment of court justices.