On Wednesday night, the state of Texas executed Larry Swearingen for the 1998 murder of 19-year-old Melissa Trotter. To the very end, Swearingen maintained his innocence and claimed forensic science exonerated him. The 48-year-old was arrested for unrelated traffic charges three days after Trotter’s disappearance, but three weeks before her body was found. Nine medical experts say Trotter had likely been killed more than a week after Swearingen had been imprisoned, and other forensic experts say the prosecutor’s so-called “smoking gun”—a pair of pantyhose matching the half found around Trotter’s neck—was not actually from the same pair. [h/t Washington Post]

Swearingen’s last appeal was denied by the U.S. Supreme Court on Wednesday evening.

Prosecutors say other evidence against Swearingen, who had a history of violence against women, could not be ignored. Trotter had told friends that she and Swearingen, who was married at the time, were dating. Swearingen says that explains why her hair was found in his truck. In December of 1998, Trotter met Swearingen in the student center of what is now Lone Star College. Swearingen says he left alone. Other witnesses say they remember seeing Trotter eating alone, or maybe eating with a man other than Swearingen. In any case, she was not seen alive again.

That afternoon, Swearingen’s wife came home to find the family’s trailer a mess. Swearingen claimed the home had been burglarized, a statement police now believe to be a lie. He also misled police about his whereabouts and fled arrest. On the third search of the trailer, police found half a pair of pantyhose they claimed matched a pair found around Trotter’s neck.

However, Swearingen’s lawyers have since provided evidence that throws this claim into doubt—a detail the jury who found Swearingen guilty never heard. The jury also never heard the testimony of multiple forensic experts who say Swearingen couldn’t have killed Trotter because he had likely already been in jail for a week when she died. Prosecutors argued that the science “post-mortem interval” was too inexact to be taken seriously.

“Swearingen has not come close to establishing that ‘no reasonable fact-finder’ would have found him guilty,” wrote Judge Stuart Kyle Duncan, a recent appointee of President Donald Trump to the U.S. Court of Appeals for the 5th Circuit.

Swearingen owned up to past mistakes in an interview with The Washington Post, saying he “put himself in a perfect position to be framed for murder.”

“In my youth, I made a lot of stupid mistakes,” he said. “I was philandering with Melissa and other women instead of taking care of my wife and kids. I had been violent with both women and men.”

However, Swearingen continued to insist he was innocent of the crime for which he was being executed. “Texas murdered an innocent man,” he wrote in a statement to The Washington Post. “I feel certain that my death can be a catalyst to change the insane legal system of Texas which could allow this to happen.”

Swearingen was executed at 7:47 on Wednesday night. His final words were “Lord, forgive them. They don’t know what they are doing.”