A U.S. Supreme Court ruling cleared the way for Texas to carry out its 600th execution on Thursday, May 14.

Edward Busby's execution had been on hold for nearly a week after the 5th U.S. Circuit Court of Appeals issued a temporary stay over his intellectual disabilities. The state appealed the ruling and Busby's fate was unclear until the Supreme Court's ruling came in late on Thursday, May 14.

Three hours later, Texas executed him. Busby was pronounced dead at 8:11 p.m. CT

Liberal justices Elena Kagan, Ketanji Brown Jackson and Sonia Sotomayor opposed the ruling. Jackson wrote in a dissenting opinion that Texas's own expert found that Busby was too intellectually disabled to be executed.

"In capital cases, we rarely intervene to preserve life," Jackson wrote in the dissenting opinion. "I cannot understand the Court’s rush to extinguish it, much less in the circumstances of this case."

Busby was convicted of the 2004 robbery and murder of a 77-year-old former Texas Christian University professor named Laura Lee Crane, who was attacked while on a grocery store run in Fort Worth.

In his last words, Busby asked a room full of witnesses, including family members of Crane's, not to hate him and to find it in their hearts to forgive him.

"Ms. Crane was a lovely woman, I never meant anything bad to happen to her," he said as he lay strapped to a gurney in the death chamber, according to the Texas Department of Corrections. "I am so sorry ... I've hurt your family, I've hurt my family, and I wish I could take it all back. With all my heart I wish I could take it back."

Texas had executed 599 inmates since 1976, hundreds more than any other state in the nation before Busby's execution, according to the Death Penalty Information Center, which tracks executions in the U.S.

"Mr. Busby will become the 600th per­son exe­cut­ed in Texas in the last 50 years," the organization said in a post about what the milestone means for the state and the nation. The agency said that Busby's case is illustrative of how the death penalty is carried out in the U.S. for inmates of color and those with intellectual disabilities.

Here's what else you need to know about the case.

On Jan. 30, 2004, 77-year-old Laura Lee Crane was on a grocery store run near her home in Fort Worth when her nightmare began. Edward Busby and his girlfriend kidnapped the retired Texas Christian University professor, put her in the trunk of her own car and wrapped her head in duct tape, according to court records.

She suffocated to death.

"The trunk became her coffin," prosecutor Greg Miller said during Busby's trial, according to an archived news report. "The car itself became her funeral hearse."

Busby has always maintained that he never meant to kill Crane and that he thought he had wrapped the duct tape around her head in such a way that she could still breathe. He said the plan was to let her go when they were far enough away from Oklahoma.

"I just want everyone to know that it wasn't my intention for that lady to die," he said in a tearful jailhouse interview with the Fort Worth Star-Telegram in 2004. "I don't know what happened. I was up for two days smoking crack."

Crane's body was wrapped in a white sheet and left on the side of a highway near Davis, Oklahoma. Busby led authorities to the location.

On Friday, May 8, the 5th U.S. Circuit Court of Appeals issued a temporary stay in Busby's execution less than a week before it was scheduled.

The court cited an upcoming Alabama case that stands to change how an inmate's intellectual disabilities are determined.

"In a matter of life and death, we must be certain that we apply the proper constitutional rule as to whether and how to determine intellectual disability before states may execute defendants for capital crimes," 5th Circuit Judge Stephen Higginson wrote, "especially when it is a rule that the Supreme Court imminently will clarify.”

The Supreme Court justices are considering how to weigh multiple IQ scores when determining if a death row inmate’s intellectual disability is severe enough that it would be cruel and unusual punishment to execute him.

The Supreme Court could have allowed Busby's stay to remain in place as they decided the issue but the majority ruled to allow it to move forward.

Busby's execution is the 12th in the nation this year and the fourth in Texas.

It's also the second execution alone on Thursday. Earlier in the day, Oklahoma executed Raymond Eugene Johnson for the brutal 2007 murders of his ex-girlfriend, 24-year-old Brooke Whitaker, and her 7-month-old baby daughter Kya.

Next week, three states plan to carry out executions: Arizona, Tennessee and Florida.

Contributing: Maureen Groppe

Amanda Lee Myers is a senior crime reporter who covers the death penalty, cold case investigations and breaking news for USA TODAY. Follow her on X at @amandaleeusat

This article originally appeared on USA TODAY: Killer becomes 600th executed by Texas after Supreme Court clears the way