Timeline of events involving capital punishment in Oklahoma

Oklahoma conducted 112 executions from 1976 to October 2015, when the state imposed a moratorium following three consecutive flawed executions or attempted executions. That number rose to 113 Thursday when Oklahoma put John Marion Grant to death by lethal injection, the state's first execution in more than six years.

A timeline of key events involving the moratorium and steps Oklahoma took to resume lethal injections:

— April 29, 2014: Clayton Lockett writhes and groans on the gurney as Oklahoma uses the surgical sedative midazolam for the first time during an execution. Then-state prisons director Robert Patton halts the execution process, but Lockett dies 43 minutes later. A second execution set that night, for Charles Warner, is postponed. The state later says an improperly placed intravenous line — not the new drug mix — caused problems.

— June 25, 2014: Inmates sue Oklahoma, alleging the state unconstitutionally allows an "ever-changing array of untried drugs" during executions.

— Dec. 22, 2014: A federal judge declares Oklahoma's lethal injection protocol constitutional. The U.S. Supreme Court says later it will consider whether Oklahoma can use midazolam during executions, but it doesn't disrupt Warner's rescheduled execution.

— Jan. 15, 2015: Oklahoma executes Warner for the 1997 killing of his roommate's infant daughter. "My body is on fire," he says after receiving midazolam, though he shows no other signs of distress.

— April 18, 2015: Gov. Mary Fallin signs a bill into law making Oklahoma the first state to approve the use of nitrogen gas for executions.

— June 29, 2015: A divided U.S. Supreme Court upholds Oklahoma's use of midazolam during executions.

— Sept. 30, 2015: Prison officials prepare to execute Richard Glossip, but Fallin issues a 37-day stay, saying the state Department of Corrections received the wrong drug, potassium acetate, rather than the potassium chloride listed in Oklahoma's execution protocol.

— Oct. 2, 2015: The state Court of Criminal Appeals, at the request of state Attorney General Scott Pruitt puts all Oklahoma executions on indefinite hold. Pruitt calls for an inquiry into the state's execution procedures.

— Oct. 8, 2015: The Oklahoman newspaper reports that the state used potassium acetate, not potassium chloride, to execute Warner. Fallin agrees all executions should be delayed after an autopsy report revealed the wrong drug was used.

— May 19, 2016: An Oklahoma grand jury investigating the execution procedures issues its 106-page report with no indictments.

— April 25, 2017: A bipartisan commission recommends extending a moratorium on executions until major changes are made to the state’s capital punishment system.

— March 18, 2018: Oklahoma officials announce plans to develop protocols to use nitrogen gas to execute inmates.

— Feb. 13, 2020: Oklahoma officials announce plans to resume executions by using a three-drug lethal injection protocol.

— Sept. 20, 2021: The Oklahoma Court of Criminal Appeals schedules seven executions.

— Oct. 29, 2021: Oklahoma executes John Marion Grant by lethal injection after the U.S. Supreme Court lifts stays of execution that the 10th U.S. Circuit Court of Appeals had put in place the day before.