(CNN) -- [Breaking news update at 5:13 p.m. ET Tuesday]
A federal appeals court has stayed the Texas execution of Robert James Campbell, a convicted rapist and murderer. Campbell's execution had been scheduled for Tuesday.
Texas to execute 'mildly retarded' murderer tonight, defense says
(CNN) -- Texas plans to put to death Tuesday a convicted rapist and murderer who, a neuropsychologist says, is "mildly mentally retarded," in the nation's first execution since a botched lethal injection in Oklahoma left an inmate writhing in pain before death.
Robert James Campbell's defense team is challenging, on a variety of grounds, the state's decision to execute him, including ineffective assistance of counsel, state misconduct, Texas' refusal to divulge the source of its execution drugs and the man's mental capacity.
In 2002, the U.S. Supreme Court concluded "the mentally retarded should be categorically excluded from execution."
The U.S. Fifth Circuit Court of Appeals denied motions for a stay. The motions cited the mental retardation and drug-source claims.
Texas Attorney General Greg Abbott, in a petition contesting the defense claims of mental retardation, questioned why Campbell waited until 12 years after a court had determined his mental state to raise the claims.
"Campbell's last-minute claim of mental retardation, which was previously raised and rejected in the federal and state courts does not warrant review. Campbell is not mentally retarded," according to pertinent case law, Abbott contends.
The execution of Campbell, 41, is slated for 7 p.m. ET at the Texas State Penitentiary at Huntsville, about 70 miles north of Houston. The facility, nicknamed "Walls Unit" for its red brick facades, has hosted 876 executions since 1924.
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According to court documents and the Texas Department of Criminal Justice, Campbell was involved in a string of armed carjackings in 1990 and 1991. In one incident, Alexandra Rendon, a 20-year-old Houston bank employee, was snatched from a gas station, robbed, sexually assaulted and fatally shot.
"Mr. Campbell gave Ms. Rendon's coat to his mother, and her jewelry to his girlfriend, as gifts; he also drove Ms. Rendon's car openly in his own neighborhood, and told people he had been involved in the crime," according to his application for post-conviction relief.
These facts are key, as the defense team says they indicate that "Mr. Campbell demonstrates no criminal sophistication."
Questions about competence
Testing showed Campbell had "applied academic skills consistent with an individual midway through fifth grade," according to court documents, and while he was able to count and add change, he was inconsistent "calculating change from a purchase."
He also asked a friend for help reading a non-digital watch, and an informant told the court Campbell could not read a car's gas gauge and "always had to ask others whether there was enough fuel to get to the destination," the documents say.
Dr. Leslie Rosenstein, a clinical neuropsychologist, diagnosed Campbell with "mild mental retardation," saying his performance on recent tests was consistent with his standardized intelligence test scores when he was a child, according to court documents.
Campbell's defense team alleges the Texas Department of Criminal Justice was aware of Campbell's low test scores, yet told the team in 2003 that his only IQ test yielded a score of 84, well above the threshold range for mental retardation.
But as Judge Elsa Alcala wrote last week in her dissent to the Texas Court of Criminal Appeals' 5-4 decision, a defense team later learned the Department of Criminal Justice administered a test in 1992, on which Campbell scored a 71. Alcala described it as "a score that, after applying the standard of margin of error, would indicate mental retardation."
Had the department not "misinformed" Campbell's defense, the judge wrote, "then this court would have had IQ testing supportive of applicant's mental-retardation claim." Also influencing the dissent is that Rosenstein had deemed the 1990 test score of 84 "unreliable."
"This court should not base its decisions that determine whether a person will live or be executed based on misinformation or wholly inadequate information," Elsa concluded in her dissent.
Questions over execution drug mixes
Campbell's attorneys also are challenging the method by which Texas intends to execute Campbell.
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EE.UU.: agónica muerte de un reo
The constitutionality of lethal injection drugs and drug cocktails has made headlines since last year, when European manufacturers -- including Denmark-based Lundbeck, which manufactures pentobarbital -- banned U.S. prisons from using their drugs in executions. Many states were left to find new drug protocols.
Campbell's defense cites in its appeal to the U.S. Supreme Court last month's botched execution in Oklahoma, in which a three-drug cocktail was used to to try to put to death convicted murderer Clayton Lockett. The provenance of the drugs was shielded by Oklahoma law. Lockett reportedly twitched, spoke and writhed in pain for about 40 minutes before dying of a massive heart attack.
Death row inmate Charles Warner was scheduled to die in Oklahoma the same day, but the execution was postponed. The Oklahoma Court of Criminal Appeals last week extended the stay until November 13.
"We are very pleased that the (attorney general) agrees at least 6 months is necessary before any execution in Oklahoma can take place, given the need for a full investigation to be conducted into Clayton Lockett's agonizing botched execution, and the Department of Corrections' own recognition that protocol revisions and extensive retraining are necessary," Warner's attorney, Madeline Cohen, said.
In Campbell's case, Texas intends to use pentobarbital, and Campbell's lawyers point out that the drug is no longer available in regulated form and can be obtained only via so-called "compounding pharmacies," which operate outside of U.S. Food and Drug Administration oversight.
Arguing Lockett was "subjected to a torturous execution that undeniably violated his Eighth Amendment" rights, the defense says that pentobarbital also poses concerns after Oklahoma inmate Michael Lee Wilson complained during a January execution, "I feel my whole body burning."
Texas' Jose Luis Villegas also complained of a burning sensation during his April execution, and he was executed "using compounded pentobarbital from the same batch intended for Mr. Campbell," the defense's appeal says.
Campbell's attorneys say Texas' refusal to disclose the "source, efficacy and potency" of the drug raises issues similar to those in Oklahoma. It's not about which drugs are used, Campbell's defense wrote in its appeal, but about the transparency of the entire process.
The Department of Criminal Justice, in its response, said that the drug that is to be used has "been independently tested at 108% potency and is free of contaminants. TDCJ has successfully carried out, without incident, seven previous executions with pentobarbital from a different compounding pharmacy and three with pentobarbital from the same source as will be used in Campbell's execution."
"What the events in Oklahoma have made clear is that the risk of torture and a clearly cruel and unusual outcome has been proved to be a very real threat when states aren't required to facilitate executions with the transparency and accountability and disclosure of the sort sought -- and denied -- in Oklahoma," the court document says.
"In short, the events in Oklahoma have made clear that the risk of inhumane executions is substantial, including in Texas."