Twelve years ago, Robert Sparks told police he killed his wife and two stepsons, ages 10 and 9, by repeatedly stabbing them in their Dallas home in the middle of the night. He then confessed to raping his 12- and 14-year-old stepdaughters.

He told investigators his family had been poisoning him; he wanted to be tested for poison and for the girls to undergo polygraph tests, according to court records. He said a voice told him to kill his family.

On Wednesday, Sparks, 45, was executed for the deaths of his stepsons, Raekwon Agnew and Harold Sublet Jr. His siblings and nephew watched through a viewing glass in one room, according to a prison witness list. Seven of the victims’ family members — including the two women he raped as girls and Harold’s father — had indicated they would watch from a room next door. But only six actually did so, according to a spokesperson, who did not know which relative was absent.

“I am sorry for the hard times and what hurts me is that I hurt y’all,” he told his family in his final statement. “… I love y’all. I am ready.”

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At 6:39 p.m., he was pronounced dead on a prison gurney, 23 minutes after being injected with a lethal dose of pentobarbital.

Starks’ lawyers fought until the end for more time and resources to fully prepare a filing arguing that Sparks was intellectually disabled, which would have legally barred him from execution. And they had long contended his trial was tainted by false testimony and a bailiff who wore a tie with a syringe on it during jury deliberations. The U.S. Supreme Court denied his final appeal about an hour before his execution was scheduled to begin, but Justice Sonia Sotomayor took note of the bailiff’s attire, calling it “disturbing.”

“That an officer of the court conducted himself in such a manner is deeply troubling,” she wrote in the order, though she didn’t disagree with the court’s denial since legal issues with the tie had already been argued in lower courts. “I nevertheless hope that presiding judges aware of this kind of behavior would see fit to intervene in future cases by completely removing the offending item or court officer from the jury’s presence.”

Sparks was diagnosed as psychotic with delusions and with schizoaffective disorder, according to court records. At his trial, Dallas County prosecutors detailed how Sparks called police after the murders and later confessed on tape to killing the boys, as well as his wife, Chare Agnew. According to WFAA-TV, Sparks said he had been recording his family because he thought they were poisoning him, and he threatened to kill Agnew if he found out she had been.

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When everyone was asleep in September 2007, he stabbed his wife 18 times in their bed, court records state. He then woke the boys and stabbed them repeatedly — Harold at least 45 times.

At the trial, emotions ran high. The court was disrupted several times by Harold’s father, who jumped up and ran toward Sparks when attorneys detailed how his son died, according to court records. A large blade found in the gallery disrupted court proceedings one day. And closing arguments were delayed in the guilt phase of the trial after Sparks apparently tried to kill himself, The Dallas Morning Newsreported. Ultimately, he was convicted of capital murder and sentenced to death in December 2008.

In recent court filings, Sparks’ attorneys asked for funds to hire a neuropsychologist to determine if Sparks was intellectually disabled. They said things like an IQ score of 75 (a borderline number for the disability), his struggle in special education classes, and poor learning and memory indicate a strong possibility Sparks would be ineligible for the death penalty under U.S. Supreme Court precedent that forbids execution of the intellectually disabled.

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“Without a stay of execution, it is likely that Texas will execute an intellectually disabled man,” Sparks’ attorney, Jonathan Landers, wrote in a federal district court filing.

Intellectual disability is often discussed in Texas death penalty cases since the U.S. Supreme Court slammed Texas for a second time in February and invalidated its method of determining whether a death penalty inmate is disabled. Sparks’ lawyers said the appeal wasn’t brought forward earlier because Texas’ old method of determining intellectual disability was more restrictive than current medical standards. They argued that now Sparks’ low functioning, in addition to his borderline IQ of 75, “necessitates a full intellectual disability analysis.”

A federal district court judge denied the request for funds and a stop to his execution last month. U.S. District Judge David Godbey said Sparks already had a full analysis before trial, when his IQ score was given, and he was not deemed intellectually disabled. An appellate court also rebuked Sparks for first raising the claim of intellectual disability months before his execution.

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In final filings before the U.S. Supreme Court, Sparks’ argument hinged on behavior at his trial. His lawyers said false testimony from a witness and a bailiff’s wardrobe affected the jury.

Sparks’ lawyers said a state witness falsely claimed at trial that if sentenced to life in prison instead of death, Sparks would automatically be inserted into lower-security housing, providing the chance to eat and socialize with other inmates. Sparks’ attorneys said this influenced the jury to lean toward a death sentence and that it was likely he would have been in more restrictive custody based on his previous jail disciplinary action.

They also said his right to a fair trial and impartial jury were denied when a bailiff, Bobby Moorehead, wore a homemade tie depicting a syringe on the day the jury began weighing Sparks’ sentence. Moorehead sat directly behind Sparks, within view of the jury. He later admitted the tie was to show his support for the death penalty, according to Sparks’ filing.

The Texas Attorney General’s Office said the custody level testimony was corrected on cross examination to acknowledge Sparks could have had more restrictions and argued that the initial statements don’t outweigh the viciousness of his crime. It also argued that Sparks can’t prove any jurors even saw Moorehead’s tie, a point Sotomayor acknowledged when explaining why she did not disagree with the court’s denial of Sparks’ final appeal.

The main argument by the state, however, was that the public’s interest lay in executing Sparks’ sentence.

“Certainly, the State has a strong interest in carrying out a death sentence imposed for a horrific capital murder wherein Sparks murdered two children and raped two more,” wrote Assistant Attorney General Ellen Stewart-Klein.

Sparks was the seventh person executed in Texas in 2019 and the 16th in the nation. Seven more men are set for execution in Texas this year, and two more have recently been scheduled for 2020.