US

Oklahoma halts execution of inmate writhing on gurney; man dies later of heart attack

  • Protester John Walters of Oklahoma City holds a sign urging Gov. Mary Fallin to issue a stay in the execution of two inmates, near the Governor's Mansion in Oklahoma City on Tuesday, April 29, 2014. A botched execution that used a new drug combination left an Oklahoma inmate writhing and clenching his teeth on the gurney Tuesday, leading prison officials to halt the proceedings before the inmate's eventual death from a heart attack. (AP Photo/The Oklahoman, KT King)

    Protester John Walters of Oklahoma City holds a sign urging Gov. Mary Fallin to issue a stay in the execution of two inmates, near the Governor's Mansion in Oklahoma City on Tuesday, April 29, 2014. A botched execution that used a new drug combination left an Oklahoma inmate writhing and clenching his teeth on the gurney Tuesday, leading prison officials to halt the proceedings before the inmate's eventual death from a heart attack. (AP Photo/The Oklahoman, KT King)  (The Associated Press)

  • Fannie Bates of Oklahoma City holds a sign urging Gov. Mary Fallin to issue a stay in the execution of two inmates, during a protest Tuesday, April 29, 2014, near the Governor's Mansion in Oklahoma City. A botched execution that used a new drug combination left an Oklahoma inmate writhing and clenching his teeth on the gurney later Tuesday, leading prison officials to halt the proceedings before the inmate's eventual death from a heart attack. (AP Photo/The Oklahoman, KT King)

    Fannie Bates of Oklahoma City holds a sign urging Gov. Mary Fallin to issue a stay in the execution of two inmates, during a protest Tuesday, April 29, 2014, near the Governor's Mansion in Oklahoma City. A botched execution that used a new drug combination left an Oklahoma inmate writhing and clenching his teeth on the gurney later Tuesday, leading prison officials to halt the proceedings before the inmate's eventual death from a heart attack. (AP Photo/The Oklahoman, KT King)  (The Associated Press)

  • FILE - This June 29, 2011 file photo provided by the Oklahoma Department of Corrections shows Clayton Lockett. Oklahoma prison officials halted the execution of Lockett Tuesday, April 29, 2014,  after the delivery of a new three-drug combination failed to go as planned.. (AP Photo/Oklahoma Department of Corrections, File)

    FILE - This June 29, 2011 file photo provided by the Oklahoma Department of Corrections shows Clayton Lockett. Oklahoma prison officials halted the execution of Lockett Tuesday, April 29, 2014, after the delivery of a new three-drug combination failed to go as planned.. (AP Photo/Oklahoma Department of Corrections, File)  (The Associated Press)

Oklahoma prison officials halted an inmate's execution after a new drug combination left him writhing and clenching his teeth on the gurney. He later died of a heart attack.

Thirty-eight-year-old Clayton Lockett was declared unconscious 10 minutes after the first of the three-drug combination was administered Tuesday. Three minutes later he began breathing heavily, writhing, clenching his teeth and straining to lift his head off the pillow.

The blinds were lowered to prevent those in the viewing gallery from watching. The state's top prison official eventually halted the proceedings.

Lockett died of a heart attack a short time later.

Gov. Mary Fallin ordered a 14-day stay of execution for death row inmate Charles Warner, who was scheduled to die two hours after Lockett.