A full review has been ordered into the execution of double murderer Joseph Wood, who took two hours to die after being given a lethal injection.
Arizona's Governor Jan Brewer said that while justice had been done she was concerned by how long the lethal injection procedure took.
She said: "One thing is certain, however, inmate Wood died in a lawful manner and by eyewitness and medical accounts he did not suffer.
"This is in stark comparison to the gruesome, vicious suffering that he inflicted on his two victims, and the lifetime of suffering he has caused their family."
More top news
Satellite images have revealed the extent of the damage to the ancient Temple of Bel in Syria's Palmyra city by Islamic State jihadists.
Nearly half of all young people are bullied at school each day with many left feeling suicidal due to the experience, according to a survey
Thousands of pounds of NHS cash is being spent on holidays, aromatherapy and even summer houses for patients, according to research