WASHINGTON - A US state executed a convicted murderer with an animal drug for the first time because of an anesthetic shortage, in a move critics panned as a test on a human guinea pig.
Oklahoma executed John Duty, 58 -- who in 2001 strangled his 22-year-old cellmate, Curtis Wise, while serving three life sentences -- with pentobarbital, normally used by veterinarians to put animals to sleep.
"The procedure started at 6:12 pm our time (0012 GMT). John Duty was pronounced dead at 6:18pm," Jerry Massie, a spokesman for the Oklahoma Department of Corrections, told AFP.
"His last words were: 'To the family of Curtis Wise: I'd like to make my apology. I hope one day you'll be able to forgive me, not for my sake but for your own... Thank you, Lord Jesus. I'm ready to go home,'" Massie said.
The Death Penalty Information Center, a Washington-based group that monitors capital punishment, confirmed that Duty was the first death row inmate to be executed using the drug.
For months now, several US states have struggled to find supplies of sodium thiopental -- the first and most crucial of three drugs used in lethal injections -- after its sole US manufacturer Hospira ran out of stock.
The company will resume production of the drug early next year, forcing some states to suspend executions and others to import the drug from other states or from overseas with government approval.
Oklahoma's decision to use the animal drug was approved by a US court last month in a ruling that may lead other states to adopt the procedure.
The appeals court found that the amount of pentobarbital to be used was "sufficient to induce unconsciousness in an inmate and indeed would likely be lethal in most, if not all, instances."
Capital punishment specialists meanwhile warned that the drug had not been properly vetted and might not keep inmates unconscious during the more painful subsequent injections that kill them.
And Duty's lawyers had expressed fears in court documents that their client would be used as a "guinea pig" to test the new method of execution.
In its response, Oklahoma stressed that, since pentobarbital has been widely used on animals and as a human anesthetic, its use on inmates is "hardly experimental."