A man took at least 15 minutes to die during his execution by nitrogen gas in the US state of Alabama.
Anthony Boyd, 54, was convicted of helping to burn a man alive in 1993 over a $200 (£150) cocaine debt.
He was sentenced to death for his role in killing Gregory Huguley in Talladega County.
Boyd used his final words to proclaim his innocence, saying: “I didn’t kill anybody. I didn’t participate in killing anybody.
“There can be no justice until we change this system.”
He said he wanted to express love to those who were still fighting, adding: “Let’s get it.”
Boyd was pronounced dead at 6.33pm at William C Holman Correctional Facility on Thursday.
While officials in Alabama did not reveal the exact time the gas began flowing, the execution appeared to take longer than previous cases using nitrogen gas, a method the state began using last year.
It involves a gas mask being strapped over the inmate’s face to replace breathable air with pure nitrogen gas, causing the person to die from a lack of oxygen.
At around 5.57pm, he clenched his fist, raised his hand off the gurney slightly and began shaking. He then raised his legs off the gurney.
Then at about 6.01pm, he began a long series of heavy breaths, which lasted at least 15 minutes, before he became still.
The curtain to the execution chamber was closed at 6.27pm.
The prison commissioner said the gas is typically kept flowing for five minutes after monitoring shows an inmate no longer has a heartbeat.
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‘Absolutely incompetent’
The reverend Jeff Hood, who stood by Boyd as he died, said the nitrogen gas execution was “the worst one yet”.
“I think they are absolutely incompetent when it comes to carrying out these executions,” he added.
Mr Hood said authorities in Alabama had promised the method was a “quick, painless, easy form of execution and this is by far nothing anywhere close to that.”
He said he believed Boyd planned to try to communicate through his leg movements. He said he believed there was “some level of consciousness, in my opinion, for at least 16 minutes.”
However, Alabama Corrections Commissioner John Hamm said he believed Boyd’s movements were involuntary. He said that while the execution took longer than previous ones, it was only by “just a few minutes”.
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Jury recommended death sentence
A prosecution witness at Boyd’s trial testified as part of a plea agreement that Boyd taped Mr Huguley’s feet together before another man doused him with petrol and set him on fire.
Defence lawyers said he was at a party on the night Mr Huguley was killed and that the plea deal testimony was unreliable.
However, a jury convicted Boyd of capital murder during a kidnapping and recommended he receive the death sentence by a vote of 10 to two.
Alabama Attorney General Steve Marshall said: “For more than 30 years, Boyd sought to delay justice through endless litigation, yet he never once presented evidence that the jury was wrong.”
Boyd, who had been on death row since 1995, was the latest chair of Project Hope to Abolish the Death Penalty, a campaign group founded by men on death row.
