A disabled death row inmate who killed a girl, 8, has been executed by lethal injection.
The Arizona prisoner, convicted in 1984 of the killing of the girl, has been put to death by the US in the state’s second execution since a nearly eight-year hiatus.
The 66-year-old, who was in a wheelchair, died by lethal injection at 10.16 am local time (6.16 pm BST) at the state prison in Florence, 61 miles southeast of Phoenix, for murdering Vicki Hoskinson.
Hoskinson's body was found in the desert in 1985 months after leaving her home in Tucson, the second-largest city in Arizona, on a bicycle to drop a birthday card for her aunt in a nearby postbox.
Friends and neighbours of the Hoskinson family showed their support outside the prison to remember Vicki Lynne.
“I feel like it will be a part of a closure for my childhood,” Stacy Davis, a childhood friend of Vicki Lynne, told AZ Central.
Atwood is the second Arizona inmate put to death in less than a month after Clarence Dixon's execution last month ended the southwestern state's eight-year hiatus following a failed procedure in 2014.
Atwood had defended his innocence and his lawyers made several failed pleas to have the execution halted and US District Judge Michael Liburdi decided to go ahead with the execution.
This is despite the convict saying that the state's death penalty procedures would violate his constitutional right against cruel and unusual punishment by subjecting him to unimaginable pain.
His lawyers said that Atwood, who has a degenerative spinal condition that has left him in a wheelchair, would undergo excruciating suffering if he were strapped to a gurney while lying on his back during his lethal injection execution.
The 9th U.S. Circuit Court of Appeals said Attwood could use a pillow and tilting feature on the gurney to "minimise the pain Plaintiff experiences when he lies on his back".
The Constitution said he "does not require a pain-free execution", and that Atwood's position would be similar to what he typically accepts in his cell to limit pain.
He also asked the Arizona Supreme Court to delay his execution while his lawyers claimed he is innocent of killing the little girl.
Protesters and counterprotesters lined up outside of Florence prison on Wednesday, along a barricade set up by police along the intersection of Butte and Pinal Parkway avenues, AZ Central reported.
Two weeks ago, Atwood failed to choose between lethal injection or the gas chamber, leaving him to be put to death by lethal injection, the state's default execution method.
"The state's insistence on cyanide gas is a cynical choice to force the acceptance of the danger and incompetence of its lethal injection method, at the cost of embracing Nazi methods of mass extermination," Joseph Perkovich, a lawyer for Atwood, said in an email Sunday.
Debbie Carlson, Vicki's mother, at Atwood's clemency hearing in May said his execution would bring final justice for her daughter and mark a new beginning for her family.
"We chose the death penalty because we never wanted another child to have to be faced by this monster," she said. "We wanted to make sure another family was spared and not have to live what we have lived for the last 37 1/2 years."
