Officer Gary Glover shot Eric McNac late Saturday after he allegedly made a "threatening motion," police said. They would not say what the threatening motion was.
Meanwhile, the Oklahoma State Bureau of Investigation is investigating a Sunday afternoon shooting in which a man who had held hostages was killed when he fired at Oklahoma Highway Patrol troopers at the scene.
Muskogee Sgt. Derek Apple said Monday he did not know if McNac was armed at the time of the shooting and that other investigators were unavailable to comment.
"They're still trying to put everything together," he said.
Officers responding to a 10:36 p.m. call of shots fired pulled over a white Buick that matched the description of the suspect's car.
Police reports indicate that after a 9 mm pistol was found on the driver of the car, Glover asked the other three occupants to show their hands.
At this point, McNac made the threatening motion, police said, and Glover fired one shot, striking McNac. He was taken to the Muskogee Regional Medical Center where he died later that night.
Police reports show that a quarter pound of crack cocaine was found on McNac at the hospital.
The Muskogee County District Attorney's Office will review the shooting to determine if it was justified.
Glover, who been with the Muskogee Police Department for three years, was put on routine leave with pay.
Authorities said a Johnston County man was shot and killed Sunday afternoon. Lt. Chris West said the sheriff's department responded to a hostage call and asked for the patrol's assistance.
West said that hostages were released before the patrol's hostage negotiator arrived, but the troopers were asked to remain on the scene.
The man remained barricaded in the house and fired off rounds throughout the day.
West said the man came out of the house and fired at troopers, who returned fire.
West said five troopers were place on administrative leave, a standard procedure following a shooting. He declined to release the names of the five.