Tennessee has executed a man for the 1988 murder of his girlfriend and her two young daughters despite arguments that he suffered from intellectual disabilities and concerns that his heart device would shock him back to life during the lethal injection.

The state executed Byron Black on Tuesday, Aug. 5, after Gov. Bill Lee declined requests from attorneys, advocacy groups and even some Republicans to intervene. He was pronounced dead at 10:43 a.m. CT.

“This is hurting so bad,” Black said during the execution, according to news media witnesses who saw him die and reported that he showed signs of distress.

On March 28, 1988, Angela Clay and her eldest daughter, 9-year-old Latoya, were found shot dead in bed. Clay’s other daughter, 6-year-old Lakeisha, was found dead on the floor in another bedroom with multiple gunshot wounds.

Black became the 28th inmate executed in the U.S. this year, a 10-year high, with at least nine more executions scheduled. He’s the second inmate to be put to death in Tennessee this year after a five-year break in executions in the state.

Black’s case stands out for two reasons. What his legal team said was an “undisputed intellectual disability” had many calling for a reprieve, including some Republicans. And his attorneys raised serious questions about whether Black’s implanted heart device would cause “a prolonged and torturous execution” in violation of the U.S. Constitution.

Tennessee Attorney General Jonathan Skrmetti told USA TODAY in a statement that expert testimony “refutes the suggestion that Black would suffer severe pain if executed” and that the state was seeking “to hold Black accountable for his horrific crimes.”

Here’s what you need to know about the execution, the crime and the issues surrounding the case.

What happened during Byron Black’s execution?

Multiple members of the news media who witnessed Black’s execution said he did appear to show signs of distress and said that he was in pain. His spiritual adviser, who was with him throughout the process, told him: “I’m so sorry.”

Black declined to say any last words in the death chamber but gave his attorney a message directed to his friends and family to deliver afterward.

“I love you and I won’t never forget you,” Black said, according to Henry. “All of our relationships have been very special. It was my pleasure in meeting everybody and the way we connected with each other. God bless you and thank you.”

About his mother, Black said he knows what will happen when he sees her in Heaven, according to Henry: “She will run to me and pull me in (her) arms and say, ‘Son, I’ve been be waiting for you.”

Henry had harsh words for the government for allowing the execution to proceed:

“What happened here was the result of pure, unbridled bloodlust and cowardice,” she said. “It was the brutal and unchecked abuse of government power … Today the state of Tennessee killed a gentle, kind, fragile, intellectually disabled man in violation of the laws of our country simply because they could.”

She added that “we are witnessing the erosion of the rule of law and every principle of human decency on which this country was founded. Today it was Byron. Tomorrow it will be someone you care about.”

USA TODAY was reaching out to Tennessee officials for comment.

What was Byron Black convicted of?

Black was convicted of fatally shooting his girlfriend, Angela Clay, and her two daughters: 9-year-old Latoya and 6-year-old Lakeisha. They were murdered on March 27, 1988.

At the time, Black had been on work release from prison for shooting Clay’s estranged husband and her daughters’ father, Bennie Clay, in 1986. Prosecutors told jurors at trial that Black killed Angela Clay because he was jealous of her ongoing relationship with her ex.

Investigators believe that Angela Clay and Latoya were shot as they slept, while Lakeisha appeared to have tried to escape after being wounded in the chest and pelvis.

Bennie Clay previously told The Tennessean, part of the USA TODAY Network, he believes Black killed the girls to spite him. “My kids, they were babies,” he told the newspaper. “They were smart, they were gonna be something. They never got the chance.”

More recently, he told The Tennessean he planned to attend the execution, though he said he has forgiven Black.

“God has a plan for everything,” he told the newspaper. “He had a plan when he took my girls. He needed them more than I did, I guess.”

Judge ordered Byron Black’s heart device removed before execution

On July 22, a judge ordered that a heart device implanted in Black needed to be removed at a hospital the morning of his execution, a development that appeared to complicate matters as a Nashville hospital declined to participate.

But the Tennessee Supreme Court overturned the judge’s order, and the U.S. Supreme Court backed that up, clearing the way for Black to be executed despite the heart device.

His attorneys argued that the device, designed to revive the heart, could lead to “a prolonged and torturous execution.”

“It’s horrifying to think about this frail old man being shocked over and over as the device attempts to restore his heart’s rhythm even as the State works to kill him,” Henry said in a statement.

The state argued that Black’s heart device would not cause him pain.

Robin, Maher, executive director of the nonprofit Death Penalty Information Center, told USA TODAY that an inmate being executed with a defibrillator implant was “a completely unprecedented issue.”

But, she added, “one I fear we will see again as states move toward executing aging prisoners on death row.”

Tennessee governor declined to intervene

With their arguments over Black’s heart device at the end of the legal road, his attorneys re-focused their attention on his intellectual disabilities during his final days and hours, calling on Republican Tennessee Gov. Bill Lee to stop the execution and prevent “a grotesque spectacle.”

Citing Fetal Alcohol Syndrome and exposure to toxic lead, Black’s attorneys said mental impairments meant that he always had to live with and rely on family. More recently on death row, his attorneys said that other inmates had to “do his everyday tasks for him, including cleaning his cell, doing his laundry, and microwaving his food.”

“If ever a case called for the Governor to grant clemency or, at the very least, a reprieve, it is this one,” Henry said in a statement.

The director of Tennessee Conservatives Concerned About the Death Penalty said that she supports accountability for people who commit heinous crimes, but “the law is clear that we do not execute people with intellectual disability.”

“Governor Lee can insist on accountability while ensuring that the law is also followed. A situation such as this is exactly why governors have clemency power,” Jasmine Woodson said in a statement. “Mr. Black has spent over three decades in prison for this crime and will never be released. As a conservative, I believe that he should remain behind bars, but he should not be executed.”

Lee’s office did not respond to repeated requests for comment from USA TODAY.

In his statement to USA TODAY, Attorney General Skrmetti pushed back at findings that Black was intellectually disabled and said that “over the decades, courts have uniformly denied Black’s eleven distinct attempts to overturn his murder convictions and death sentence.”

Angela Clay’s family long sought justice

Angela Clay’s sister, Linette Bell, said in a statement after the execution that it “was a long time coming.”

“Thirty-seven years is too long,” she said. “His family is going through the same thing now that we went through 37 years ago. I can’t say I’m sorry, because we never got an apology. He never apologized, and he never admitted it, even on his dying bed … He took it to his grave with him, and he knows he did it.”

Clay’s mother, 88-year-old Marie Bell, thanked God for “letting me be here to see this closure.”

“I hope that we can be in peace from this day forward,” she added.

Outside the prison ahead of the execution, Angela Clay’s niece, Nicoule Davis, told The Tennessean that “it’s time for a celebration.”

What was Byron Black’s last meal?

Black’s last meal was pizza with mushrooms and sausage, donuts, and butter pecan ice cream.

Byron Black’s execution is second in the state this year

Black is the second inmate to be executed in Tennessee this year following a five-year break in the death penalty in the state. The break followed an independent review that found the Tennessee Department of Corrections was not consistently testing execution drugs for potency and purity.

Nationwide, nine more executions are scheduled for this year, with more expected to be carried out as governors sign more death warrants. The next execution is Kayle Barrington Bates in Florida on Aug. 19 for the 1982 stabbing death of a 24-year-old woman named Janet White, who was kidnapped from her office and taken to the woods before Bates beat her, tried to rape her and ultimately killed her.

Contributing: Kelly Puente, The Tennessean

Amanda Lee Myers is a senior crime reporter for USA TODAY. Follow her on X at @amandaleeusat.