NASHVILLE, Tenn. (AP) — A Tennessee man who killed his wife and her two teenage sons was scheduled to be executed on Thursday morning, three years after he was saved by a last-minute reprieve.

Oscar Smith, 75, was scheduled to receive a lethal injection of the barbiturate pentobarbital at 10:10 a.m. Smith has always claimed to be innocent, and in an interview with The Associated Press recently, he primarily wanted to discuss the ways he felt the court system had failed him.

He was convicted of fatally stabbing and shooting his estranged wife, Judith Smith, 13-year-old Jason Burnett and 16-year-old Chad Burnett at their Nashville, Tennessee, home on Oct. 1, 1989. He was sentenced to death by a Davidson County jury in July 1990 for the murders.

In 2022, a Davidson County Criminal Court judge denied requests to reopen his case despite some new evidence that the DNA of an unknown person was on one of the murder weapons. The judge wrote that the evidence of Smith’s guilt was overwhelming and the DNA evidence did not tip the scales in his favor.

Tennessee executions have been on hold for five years, first because of COVID-19 and then because of missteps by the Tennessee Department of Correction.

Smith came within minutes of execution in 2022 before he was saved by a surprise reprieve from Republican Gov. Bill Lee. It later turned out the lethal drugs that were going to be used on him had not been properly tested. A subsequent yearlong investigation turned up numerous other problems with Tennessee executions.

The Correction Department issued new guidelines for executions in December. The new execution manual contains only a single page on the lethal injection chemicals with no specific directions for testing the drugs. It also removes the requirement that the drugs come from a licensed pharmacist. Smith’s attorney, Amy Harwell, has characterized it this way: “It’s as if, having been caught breaking their own rules, TDOC decided, ‘Let’s just not have rules.’”

The new protocols are the subject of a lawsuit filed by Smith and other death row inmates. A trial in that case is set for next January.