(Reuters) - A 70-year-old man convicted of murdering his estranged wife’s parents and brother in 1989 was executed in Texas on Thursday, hours after the U.S. Supreme Court denied a petition seeking a reprieve on grounds he received inadequate defense at his trial.

Billie Wayne Coble was pronounced dead at 6:24 p.m. CST (0024 GMT Friday) from lethal injection at the state death chamber in Huntsville, the Texas Department of Criminal Justice said in a statement.

His last words, according to the department, were: “That will be five dollars. Take care.”

It was the third execution this year in the United States and the second in Texas, which has put more inmates to death than any other state since the U.S. Supreme Court reinstated capital punishment in 1976.

Coble, a Vietnam War veteran and electrician, was convicted in 1990 of slaying his estranged wife’s mother and father, Robert and Zelda Vicha, and her brother, John “Bobby” Vicha, who was a police sergeant. Coble’s wife had sought a divorce at the time.

Coble ambushed the three victims and shot them at their home in Axtell, a small community 100 miles (160 km) north of the state capital, Austin, authorities said in court papers.

He then kidnapped his estranged wife and drove off with her.

He was chased by police and, while driving, stabbed her with a knife. He eventually crashed into a parked car and was arrested. His wife survived.

A lawyer for Coble petitioned the Supreme Court earlier this month for a stay of execution, arguing that his trial attorneys had deprived him of his constitutional right to a fair trial by putting on a shoddy defense.

According to Coble’s pleading, his defense team played Vietnam War footage for the jurors and reminded them that Coble had fought as a U.S. Marine. But his lawyers also conceded his guilt.

“Nobody expected defense counsel to proceed in this feeble manner,” Coble’s appellate attorney, A. Richard Ellis, wrote. “The move stunned the prosecution, the media, and most importantly the defendant (Coble) himself.”

The state countered in court papers that Coble had told the trial judge he was satisfied with his defense.

“The public’s interest is not advanced by staying Coble’s execution to consider a procedurally defaulted and meritless claim based on a decision handed down three decades after Coble terrorized and murdered his ex-wife’s entire family,” Texas Assistant Attorney General Gwendolyn Vindell wrote.

The Supreme Court denied Coble’s application for a stay without comment on Thursday afternoon.