An Arizona inmate took almost two hours to die by lethal injection and his lawyers said he "gasped and snorted" before succumbing in the latest botched execution to raise questions about the death penalty in the United States.
The execution of convicted double murderer Joseph Wood began at 1.52pm local time (8.52am today, NZT) at a state prison complex. The 55-year-old was pronounced dead at 3.49pm, the Arizona attorney general's office said.
"I've witnessed a number of executions before and I've never seen anything like this," one of Wood's lawyers, Dale Baich, told US newspaper The Washington Post. "Nor has an execution that I observed taken this long."
During that time, his lawyers filed an emergency appeal in federal court that sought to have the execution halted and their client given life-saving medical treatment.
The appeal said Wood had been "gasping and snorting for more than an hour", and that the procedure violated his constitutional right to be executed without suffering "cruel and unusual punishment".
Wood was still awake more than an hour after the process began, the Post reported. Baich told the newspaper the execution team announced that Wood was unconscious at 1.57pm but after this, Wood's lips began moving and he was "struggling to breathe" for the next hour and 40 minutes.
Wood had been one of six death row inmates who sued Arizona last month arguing that secrecy surrounding the drugs used in other botched executions in Ohio and Oklahoma violated their rights.
But on Wednesday the Arizona Supreme Court cleared the way for him to be put to death, lifting a hold after reviewing a last-minute appeal that involved demands for more information about the lethal drug cocktail to be used in the execution.
The execution had previously been put on hold by the 9th US Circuit Court of Appeals, which said on Saturday that Wood could suffer "irreparable harm" unless the state divulged information about the drugs and the qualifications of the medical staff conducting the execution.
Wood was sentenced to death for the 1991 shooting and killing his ex-girlfriend Debra Dietz and her father Gene.
The Arizona Department of Corrections is yet to comment.