Death row inmate Joseph Wood has died after an execution in Arizona took nearly two hours to kill him.

Joseph Wood, a double murderer, was executed by lethal injection.

His lawyers filed an appeal for an emergency stay of execution, after he had been “gasping and snorting for more than an hour” in the death chamber.

Arizona Governor Jan Brewer says she has ordered a full review of the execution, although she said that Joseph Wood “died in a lawful manner”.

Joseph Wood’s lawyers argued the extended execution process violated his right to be executed in the absence of cruel and unusual punishment.

Jan Brewer said: “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.”

The execution should have taken 10 minutes, his lawyers said, but Joseph Wood, 55, gasped more than 600 times before he died.

Joseph Wood was convicted of the 1989 murders of his estranged girlfriend Debra Dietz and her father Eugene Dietz

It began at 13:52, and Joseph Wood was pronounced dead at 15:49, one hour and 57 minutes later, according to the Arizona attorney-general’s office.

He was convicted of the 1989 murders of his estranged girlfriend Debra Dietz and her father Eugene Dietz.

Family members of the victims were unconcerned by the way the execution was carried out.

“This man conducted a horrific murder and you guys are going, let’s worry about the drugs,’’ said Richard Brown.

“Why didn’t they give him a bullet?”

Joseph Wood’s lawyers had sought to force Arizona to name the manufacturers of the drugs used in the execution, but a last-ditch ruling by the US Supreme Court cleared the way for the execution to go ahead.

In communications with Joseph Wood’s lawyers this year, Arizona officials said they would use a two-drug combination of midazolam and hydromorphone to put him to death.

However, they declined to provide further identifying information, including the name of the drug’s manufacturer, citing a state confidentiality law aimed at protecting the drug makers from reprisal.

In 2010, the sole US manufacturer of sodium thiopental, a sedative used in lethal injections, stopped producing it. States switched to pentobarbital, also a sedative, but its Danish manufacturer Lundbeck began tightly restricting its distribution to prevent it being used in executions.

And in 2011, the UK imposed export bans on three common lethal injection drugs, pentobarbital, pancuronium bromide and potassium chloride. In the same year, the EU restricted the distribution of sodium thiopental to nations that practice capital punishment.

States have experimented with other drugs since.

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