OKLAHOMA CITY – Convicted murderer Garry Thomas Allen, whose Oklahoma execution had been halted three times while legal questions about his mental health were debated, was put to death by lethal injection on Tuesday, a state prison spokesman said.

Allen, 56, killed the mother of his two children on November 21, 1986, gunning her down in front of daycare workers after she arrived to pick up the couple’s 2 – and 6-year-old sons. Gail Titsworth, 24, had moved out of Thomas’ home four days earlier and rebuffed his pleas to return.

Allen was drunk and shot the woman four times before a police officer found him in a nearby alley and shot him in the face during a struggle over the officer’s gun.

Allen lost his left eye and sustained brain damage from the gunshot wound, according to court testimony, but a jury found him competent to stand trial.

Allen, who had a long history of drug and alcohol abuse and had been hospitalized for psychological problems, insisted on entering a “blind” guilty plea to murder, meaning the plea was entered without his knowing what his punishment would be.

His plea was intended to spare the emotions of his family and the family of the woman he killed, records show.

“I can’t see making a bad matter worse, bringing up the problems we were having and what motivated me to do what I did. It just makes things worse than ever,” he said, according to court transcripts.

Years of legal appeals focused on his mental competency. In 2005 a state pardon and parole board voted 4-1 to commute Allen’s death sentence to life in prison, but Oklahoma Governor Mary Fallin overruled the recommendation earlier this year.

Defense attorneys also unsuccessfully raised claims that Allen’s mental health had deteriorated to such an extent during his years in prison that he was no longer eligible for the death penalty.

Allen was the fifth inmate executed in Oklahoma this year and the 36th in the United States. He was pronounced dead at 6:10 p.m. local time at the Oklahoma State Penitentiary in McAlester, said state prison spokesman Jerry Massie.

Allen delivered a rambling and often unintelligible final statement that touched on Tuesday’s presidential election, including a prediction that “it’s going to be a very close race,” Massie said.

(Editing by Mary Wisniewski, Corrie MacLaggan and Todd Eastham)