By Karen Brooks
AUSTIN, Texas (Reuters) - Texas executed on Tuesday a man convicted of fatally shooting two people and paralyzing a third near Houston in 1998, despite evidence that he was mentally disabled.
Milton Mathis, 32, was sentenced in 1999, before the U.S. Supreme Court ruled it unconstitutional to execute inmates with mental disabilities. His supporters had been trying for years to argue that he should be spared.
On Tuesday, a final plea to the Supreme Court to hear evidence of his mental disability was denied, and he was executed by lethal injection.
He was pronounced dead at 6:53 p.m. local time, said Jason Clark, a Texas Department of Criminal Justice spokesman.
Mathis was the 23rd person executed in the United States this year and the sixth executed in Texas, the most active death penalty state in the nation.
Shortly before he died, Mathis criticized the Texas death penalty as a "mass slaughter."
"The system has failed me. This is a miscarriage of justice," he said.
Turning to Melanie Almaguer, who has been paralyzed from the neck down since the shooting, and witnessed the execution, he said he "never meant" to hurt her, according to Clark.
"You were just in the wrong place at the wrong time," Mathis said.
His last meal included two burgers with bacon, fried pork chops, fried chicken, fried fish, chili cheese fries, regular fries, and fruit punch, Clark said.
Mathis was convicted in September 1999 of opening fire on a home in Fort Bend County, west of Houston, and killing Travis Brown and Daniel Hibbard. Almaguer, then 15, was also shot in the head.
Mathis also turned the gun on Almaguer's mother, who was in the home, but ran out of bullets, according to the state attorney general's office. He looted the home before setting it on fire, fled in Brown's car, and later told a fellow inmate that he wished he had "killed them all," according to the attorney general's office.
Most U.S. inmates with mental disabilities have been spared execution since the Supreme Court in 2002 declared it unconstitutional, said Richard Dieter, executive director of the Washington-based Death Penalty Information Center, which tracks capital punishment cases.
Those who have been executed were usually cases in which the inmate's claim of mental disability was in dispute, including the Mathis case, he said.
"People have been removed from Death Row whose convictions preceded the (Supreme Court), but disputed cases sometimes go down to the wire and even go to execution, even with the claim" of mental disabilities, he said.
After the ruling, the Supreme Court told states to come up with their own methods of determining if a person is mentally disabled, and about half of them have passed laws defining it for capital cases, Dieter said. Texas is not one of them.
Mathis, who had an eighth-grade education when he was convicted, has scored in the low 60s on several IQ tests -- including a 62 on a test administered by the state's prison system, according to an essay on the Stand Down Texas website by Mark White, a former Texas governor who opposed Mathis' execution. Stand Down Texas supports a death penalty moratorium in Texas.
Psychology experts have routinely put the standard for mental disabilities around a 70 IQ and lower.
"Mathis has suffered from obvious mental disabilities since childhood," White wrote. "He failed the first, fifth and eighth grades and dropped out of high school in ninth grade. He has had problems with functions that come easily to most of us, like dressing himself."
Texas has a particularly high burden of proof for mental disability, said Keith Hampton, an Austin defense attorney who specializes in death penalty cases.
It takes more than IQ tests, he said. Attorneys also have to prove that the inmate had disabilities before age 18, and that he or she has shown a deficit in adaptive skills, such as reading and writing and following directions.
Texas Republican Governor Rick Perry, who is considering a run for president, vetoed state legislation in 2001 that would have outlawed executing inmates with mental disabilities, saying that Texas juries should decide who to execute.
(Editing by Greg McCune)