A 67-year-old man convicted of killing four men more than three decades ago has been executed, making him the oldest of the 526 Texas prisoners put to death since the state resumed carrying out capital punishment in 1982.
Lester Bower Jr was convicted of the October 1983 fatal shootings at an airplane hangar on a ranch north of Dallas.
Prosecutors say he killed the four after stealing an airplane he had been trying to buy from one of his victims.
Bower, strapped to the death chamber stretcher, said: "Much has been said about this case. Much has been written about this case. Not all if it has been the truth. But the time for discerning truth is over and it's time to move on."
As the execution drug took effect, the snored quietly about six times and then stopped moving. He was pronounced dead at 6.36pm, 18 minutes later.
The execution came about three hours after the US Supreme Court rejected a last-ditch appeal from his Bower's lawyers arguing that trial jurors did not have the opportunity in their punishment deliberations to fully consider that Bower had no previous criminal record.
Lawyers also contended that the 5th US Circuit Court of Appeal used an incorrect legal standard when it denied an appeal for Bower a decade ago.
"This is not a typical death penalty case," his lead lawyer, Peter Buscemi, told the justices, urging a reprieve so the court "has sufficient time" to evaluate the appeal.
Stephen Hoffman, an assistant Texas attorney general, responded that 30 years of litigation was enough and justice already had been delayed "for the four families of the men that Bower slaughtered in cold blood".
The renewed late plea to the Supreme Court came after the justices in March declined to review Bower's case - although three justices, Stephen Breyer, Ruth Bader Ginsburg and Sonia Sotomayor, said they would have thrown out his death sentence.
Bower, a chemical salesman from Arlington, was arrested and charged with capital murder after the four men were found October 8, 1983.
Those killed were building contractor and B&B Ranch owner Bob Tate, 51; Grayson County Sheriff's Deputy Philip Good, 29, who sold ultralights and was trying to sell one owned by Tate; Jerry Brown, 52, a Sherman interior designer; and Ronald Mayes, 39, a former Sherman police officer.
All were "best buddies", said Marlene Bushard, Mr Good's wife, who was among the execution witnesses.
"It's very frustrating," she said. "You move on with your life and it hits you again. I'm just looking forward to moving on."
Prosecutors built a circumstantial case that Bower stole the aircraft and shot the men as they showed up that Saturday afternoon at the hangar where Bower was to complete the purchase. Parts of the plane later were found at Bower's home.
Bower initially lied to his wife and to investigators. He eventually acknowledged being at the ranch, but said the victims were alive and well when he left with the disassembled plane that he properly bought, but could produce no receipt. His lawyers suggested years later that other men involved in a drug deal gone bad were responsible for the shootings.
Bower is nearly one and a half years older than William Chappell, who was executed at age 66 in Texas in 2002.
Nationally, a 74-year-old prisoner was put to death in Alabama in 2004. Only one other executed prisoner in Texas served more time on death row than Bower.
Bower was one of two executions scheduled for this month. Another is set for June 18 and Texas Department of Criminal Justice officials said they have enough of the execution drug to carry it out.