Percy Walton's attorneys describe their client as a man who has lost all touch with reality: He keeps no personal effects in his death row cell, save for a mountain of salt and pepper packets.

He rarely speaks, although occasionally bursts into random bouts of laughter. And when asked what he believes will happen to him if he is executed, Walton responds that he'd go to Burger King, the attorneys say.

Whether Walton — who is scheduled to die by injection Thursday — is indeed insane and mentally retarded has been debated for nearly a decade. Some believe he is faking his behavior to get off death row. Others argue he simply doesn't meet the legal definition of insanity or mental retardation.

The question of his sanity is now before the U.S. Supreme Court, which has just days to decide whether to take the case and determine if Walton should be executed for the 1996 slayings of three neighbors in Danville.

Walton, 27, pleaded guilty in 1997 to the murders of Jessie and Elizabeth Kendrick, a couple in their 80s, and 33-year-old Archie Moore. The victims were robbed and shot in the head; Moore's body was found stuffed in a closet, his corpse doused in cologne. It was a crime Walton's own attorneys describe as bizarre and senseless.

"The police told me later that Daddy was face down on the carpet in the living room with his hands above his head, as if in prayer," the Kendricks' daughter, Barbara Case, 68, said softly. "Mother was in the dining area. ... He said she had begged for her life — she had begged him not to kill her."

The Supreme Court has ruled it unconstitutional to execute the insane and mentally retarded, but left definitions up to the states. In the petition to the high court, Walton's attorneys argue that Walton has schizophrenia and is incapable of understanding the concept of death, therefore making him ineligible for execution.

The petition argues that the court didn't give sufficient guidance in its Ford v. Wainwright decision in 1986, which found that executions of the insane are unconstitutional. As a result, lower courts read the decision narrowly and allow executions of mentally ill inmates whom the court intended to protect, the petition says.

A clemency request with Gov. Timothy M. Kaine further argues that Walton is mentally retarded. The Virginia attorney general's office has argued that intelligence scores taken when Walton was 17 and 18 place him above the accepted range for mental retardation, though other evaluations were conflicting.

Walton was three days from execution in 2003 when U.S. District Judge Samuel Wilson granted a temporary stay so experts could explore his mental state.

In the hearings that followed, prison guard Cecilia Turner testified that Walton wouldn't leave his cell to take a shower, complaining about a man in a white suit sitting on a gray box in his cell. Turner said she would have to convince him the imaginary man was gone before he would come out.

Prison counselors and mental health specialists told the judge they thought Walton was psychotic and delusional. While the lawyers debated in court, Walton laughed and picked his nose.

But Wilson ultimately ruled that despite Walton's problems, he understands his death sentence is punishment for his murder conviction and is therefore competent. The judge noted the testimony of a prison psychiatrist who considered Walton a "mentally limited, street-wise predator" who misled people into thinking he was crazy.

In March, the 4th U.S. Circuit Court of Appeals ruled 7-6 to affirm Wilson's decision.

"His guilt and competence have been determined by 15 judges and we agree with their findings," said Tucker Martin, a spokesman for Attorney General Bob McDonnell.

But Walton's mental state has deteriorated so much that he would probably be unaware he was dying if he was executed, his attorney Nash Bilisoly said.

"He does not comprehend any of the significance of what's going on," Bilisoly said. "He's so ill now that he just has no affect. He doesn't have understanding, comprehension nor emotion."

Virginia's death row inmates are required to decide between lethal injection and electrocution. If they refuse to choose, the default method is injection. In 2003, Walton opted to die by electrocution, later telling The Associated Press in a phone interview he had no idea why he had chosen the chair.

"I don't even know," he told the AP shortly before his scheduled 2003 execution. "I think my man with the blue shirt, he circled one of the words. He may have been my counselor. He asked me, 'Electrocution or lethal injection.' I told him I wanted electrocution. I don't know (why). I don't even know. I don't even know."

Walton's decision to die by electrocution unnerved Case, the Kendrick's daughter, who does not believe Walton was insane or mentally retarded when he murdered her parents.

"Maybe he's just gone stark raving mad being on death row," said Case. "But who knows? Only God knows."