An Arkansas man accused of fatally shooting his drinking buddy and then shooting a female Montana Highway Patrol officer was charged Saturday with deliberate homicide and attempted deliberate homicide.

Authorities said Saturday that four shots were fired at patrol trooper Mary P. Murphy, who was wounded in the chest and arm after she stopped a suspected drunken driver on U.S. 87 north of Great Falls.Murphy, 30, was in critical but stable condition Saturday, said a spokesman at Columbus Hospital in Great Falls.

Charged in the shooting was Anthony Lankford, 20, of Perryville, Ark., whom authorities described as a drifter who had been in Great Falls only a few weeks.

Lankford appeared in justice court Saturday on the formal charges. Bail remained at $250,000.

He is also accused of shooting Francis J. Cree Medicine, 24, of Browning, whose body was found in the passenger seat of the vehicle driven by Lankford.

Authorities accuse Lankford of shooting Cree Medicine once in the head as they drove along the highway. Cree Medicine was shot only minutes before Murphy pulled over the car, authorities said.

At a news conference Saturday, Cascade County Sheriff Barry Michelotti said Murphy saw the driver holding a pistol as she approached. Murphy tried to grab the pistol, and the driver fired one shot, missed and then fired two more that struck Murphy, he said.

Michelotti said the trooper then crawled quickly behind her car and that a fourth shot was fired, hitting the windshield of the patrol car.

The driver then sped off, turned on a road toward Ryan Dam on the Missouri River and was arrested minutes later after the car went over an embankment.

Michelotti said Lankford and Cree Medicine had met in a Great Falls bar early Friday morning and apparently had been drinking together after leaving Great Falls.