The state of Georgia executed a 54-year-old mentally disabled man Tuesday for killing a fellow inmate after the U.S. Supreme Court refused to review his case, the Los Angeles Times reports.

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Warren Lee Hill received a lethal injection of pentobarbital shortly after 7 p.m. local time at the Georgia Diagnostic Prison in Jackson, the news outlet writes. He was pronounced dead at 7:55 p.m., his attorney confirmed for the Times.

Hill, who reportedly had an IQ of 70, did not make a final statement.

Just 30 minutes before Hill’s execution, the Supreme Court denied a review of his case, the news site notes. The court rejected Hill’s appeal for a stay of execution in a 7-2 vote, with Justices Stephen M. Breyer and Sonia Sotomayor dissenting, the report says.

Hill’s attorneys have long argued that Hills case underscored the “barbaric” nature of the criminal justice system, the Times writes:

“Today, the court has unconscionably allowed a grotesque miscarriage of justice to occur in Georgia,” his attorney, Brian S. Kammer, said in a statement after a stay was denied. “Tonight Georgia will unconstitutionally execute Mr. Hill, a man with the emotional and cognitive ability of a young boy. This execution is an abomination.”

It was Hill’s fourth scheduled execution date, the report says:

His lethal injection has been postponed three times in as many years, each time within hours of execution – a process that his attorney described as “psychological torture.” In the days and hours leading up to Tuesday’s execution, Hill’s legal options dwindled: On Monday evening, a federal appeals court denied a request to review the issue of Hill’s mental capacity; on Tuesday morning, the Georgia State Board of Pardons and Paroles, the sole authority in the state that can commute a death sentence to life without parole, voted to deny clemency.

Hill, a former petty officer in the U.S. Navy, was sentenced to life in prison in 1986 after shooting and killing his 18-year-old girlfriend, Myra Wright, the Times writes. Four years later, he used a nail-studded board to batter to death a fellow inmate, Joseph Handspike, and was sentenced to death by a jury, the report says.

While his intellectual ability did not come up at trial, his lawyers said he had the mental capacity of an 11-year-old child. The state argued, however, that his mental disability had not been proven beyond a reasonable doubt, as required by Georgia law. The Times writes:

“It’s been a very difficult day,” said Kammer, after informing Hill by telephone that his petitions had been denied. “He’s out of my hands now. They’re going to execute him. To be honest, I’m just at a loss for words.”

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