A death row inmate "gasped and snorted" as he took two hours to die by lethal injection in the latest "botched" execution in America, Reuters reported.
Double killer Wood, 55, was given a lethal injection of drugs at 1.52pm local time but was not pronounced dead until 3.49pm, the Arizona attorney general's office said.
Prior to his execution Wood was one of six death row inmates who sued Arizona arguing secrecy surrounding the drugs used in other botched executions in Ohio and Oklahoma violated their human rights.
His death raises questions about the use of the death penalty in the US.
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