By Steve Olafson
OKLAHOMA CITY (Reuters) - An Oklahoma man convicted of killing his former girlfriend and her two young children in 1993 is scheduled to be executed on Tuesday, when he would become the 27th prisoner put to death in the United States this year.
Michael Hooper drove his ex-girlfriend Cynthia Jarman and her children, Timothy, 3, and Tonya, 5, to a field where he shot each of them twice in the head and buried them in a shallow grave. Their bodies were found three days later on December 10, 1993.
Police reports revealed Hooper and Jarman previously had been in a "physically violent relationship," the state attorney general's office said.
Hooper's first death sentence in 1995 was overturned seven years later by a federal appeals court that found he had ineffective counsel. He waived his right to be sentenced by a jury at a new punishment hearing, and a judge re-imposed the death sentence in 2004.
Hooper, 39, also waived his right to appear before the state pardons and parole board but last week attempted to block his execution by challenging the three-drug protocol used to execute condemned killers in Oklahoma.
A federal judge in Oklahoma City and the U.S. 10th Circuit Court of Appeals in Denver rejected Hooper's challenge to the state's method of lethal injection, which he contended was unconstitutional because it had the potential to cause great pain.
Earlier this year, Oklahoma was down to one final dose of pentobarbital, one of three drugs used to execute condemned inmates, but it obtained 20 more doses since then, according to state prison spokesman Jerry Massie.
Hooper's execution is scheduled for 6 p.m. local time (CDT) at the state prison in McAlester.
He has requested a variety of fruit along with cranberry juice and coffee for his last meal, Massie said.
Oklahoma has put three inmates to death this year, according to the Death Penalty Information Center in Washington.
(Editing by Corrie MacLaggan and David Brunnstrom)