By David Schwartz and Karen Brooks
(Reuters) - An Arizona man convicted of strangling and stabbing his adoptive mother and a Texas man who confessed to being the ringleader of a ruthless band of murderers, are set to be executed on Wednesday by lethal injection.
Robert Henry Moormann, 63, is scheduled to be executed at 10 a.m. local time at the state prison complex in Florence, Arizona about 60 miles southeast of Phoenix.
George Rivas, 41, is scheduled to be put to death at a prison in Huntsville, Texas sometime after 6 p.m. local time.
They would be the fifth and sixth inmates put to death in the United States this year.
Moormann was serving a sentence of nine years to life at the Florence prison when he was given a compassionate furlough in January 1984 to visit with his mother.
Authorities said Moormann bound and gagged the 74-year-old woman at the motel where she was staying, before he strangled and stabbed her. He later chopped the body up and disposed of the parts in dumpsters throughout Florence.
At the time of the killing, Moormann was already in prison for kidnapping an 8-year-old girl.
After killing his mother, he went to a convenience store sometime the next morning and bought two knives and later asked that there be no maid service because his mother was ill.
Authorities said he went to several businesses in the area later that day asking if he could dispose of spoiled meat or animal guts. Moormann also called a prison officer and convinced him to dispose of a box of what he said was dog bones and garbage.
The bones were examined and determined to be human.
Moormann was convicted of first-degree murder on April 4, 1985 after a jury rejected his insanity defense. Jurors took two hours to reach a verdict.
In a flurry of last-minute appeals, defense attorneys have sought to block the execution by claiming that the convicted murderer is mentally retarded and cannot legally be put to death.
Attorneys also objected to the state changing the drugs it uses for the execution, challenging the decision to switch to one drug from a three-drug protocol. The state Department of Corrections on Monday informed the Arizona Supreme Court of the change.
In Texas, Rivas is scheduled to die for his role in the murder of police officer Aubrey Hawkins outside an Oshman's Superstore on Christmas Eve 2000 in Irving, next to Dallas.
Rivas was the confessed ringleader of a group that came to be known as the "Texas Seven," a band of convicted robbers, rapists, and murderers that broke out of a maximum security prison in Karnes County about an hour southeast of San Antonio on December 13, 2000.
At the time, Rivas was serving 17 life sentences for several crimes, including aggravated kidnapping, according to the Texas Attorney General's office.
After a series of robberies in other Texas cities, the group posed as security guards and shoppers and held up the Oshman's in Irving, killing Hawkins near the loading dock as they fled with more than $70,000 in cash, 44 firearms, ammunition, and other goods from the store, as well as employees' jewelry and wallets.
Hawkins died instantly from nearly a dozen gunshots from at least five guns being fired from three different directions in less than 60 seconds, according to the Texas Attorney General's Office. He was then run over with the SUV Rivas had stolen from the store's manager and dragged 10 feet before the group escaped.
After a gripping nationwide manhunt, the fugitives were found in late January 2001 in Colorado. Rivas has argued that he shot Hawkins because he saw him go for his gun, but that he was not trying to kill him.
Rivas, who was shot during the confrontation at Oshman's, later told reporters that he deserved to die for his crimes. In an interview published on Sunday in the Fort Worth Star-Telegram, Rivas said his appeals were exhausted and that he is ready to be executed.
One gang member, Larry Harper, committed suicide before he could be arrested. Another, Michael Rodriguez, was executed in 2008. The remaining four have all been convicted of capital murder and are on death row in Texas. Donald Newbury was scheduled to be executed earlier this month, but it was stayed pending the outcome of an unrelated Supreme Court case.
Rivas would be the second person executed this year in Texas, which executed 13 people in 2011 and has put to death more than four times as many people as any other state since the United States reinstated the death penalty in 1976, according to the Death Penalty Information Center.
Barring a reprieve, Moormann will be the first inmate executed in Arizona this year and the 29th since the death penalty was reinstated there in 1992.
(Editing by Tim Gaynor and Greg McCune)