OKLAHOMA CITY (AP) -- The night that Oklahoma City Master Patrolman Richard O. Riggs was gunned down was the first time he went out as a partner with rookie officer Ronnie Gravel.
Riggs spotted a van he thought was used in the nearby armed robbery of a store minutes earlier on the evening of Jan. 7, 1986. He was fatally shot twice as he approached a man on a pay phone outside the van at a Phillips 66 service station in northeast Oklahoma City.
Ronald Keith Boyd is scheduled to face execution by injection early Thursday for the shooting.
Riggs, 32, managed to return fire along with Gravel, who was not hurt.
"I just wish he was man enough ... had the guts enough, to admit he made a bad mistake," Gravel, speaking to the clemency board, said of Boyd.
A writ of original habeas corpus was filed Monday by Boyd's attorney, David Autry, with the U.S. Supreme Court, asking that the court look at the evidence in the case again. A spokesman in the attorney general's office said he anticipated that it would not be upheld.
Boyd, 42, continues to claim he is innocent of the shooting, despite witness accounts and expert testimony.
"I never shot no one," Boyd told the state Pardon and Parole board in March, claiming he had no gunpowder residue on his hands and could not be the shooter.
Prosecutors said Boyd was arrested a day after the shooting following a standoff at an Oklahoma City residence. They said it provided plenty of time to wash his hands.
In Boyd's clemency hearing, Assistant Attorney General Seth S. Branham called Boyd's claim a "fantasy of innocence."
Boyd claimed at his trial that the shooting was not intentional. That was questioned by prosecutors and contradicted by expert witnesses.
"You don't normally accidentally fire twice," Assistant District Attorney Ray C. Elliott pointed out at Boyd's preliminary trial.
Oklahoma Medical Examiner Dr. Chai Choi found during the autopsy that the second shot was a contact wound, fired at close proximity to Riggs' chest.
Rigg's family including his parents, Richard L. and Betty Riggs, a sister and three brothers have said they are planning to attend Boyd's execution. Several Oklahoma City police officers also may attend, said Charlie Price, a spokesman for the attorney general's office.
Former police Chief Robert Wilder remembered Riggs shortly after the fatal shooting as "a very caring police officer," and said Riggs had received several commendations from his superiors.
Riggs was named "Officer of the Month" in April 1985 for his training of rookie officers, the same month he was promoted to master patrol officer.
Boyd has requested a last meal of catfish, French fries, plums and grapes, strawberry shortcake and a cherry Sprite.