Shortly after a woman was killed in Alexandria by a sniper's bullet last month, her accused slayer, Marine Cpl. Phillip Steeves, emptied six shells from a revolver and said he "couldn't believe they were all empty," a fellow Marine Testified yesterday.

Cpl. Michael Cebulski took the stand at a preliminary hearing for Steeves, who is charged with the May 20 slaying of Mary Ann Montecalvo of Arlington as she drove along North Henry Street.

Steeves returned to Cebulski's home in the Belleview military housing complex in Southeast Washington at about 1 a.m. and "just brought it into (a bedroom) and started unloading it," Cebulski said.

"He said he couldn't believe they were all empty and that he couldn't remember what happened," Cebulski testified, adding that Steeves didn't say where he had been or what he had fired at.

General District Court Judge Daniel Fairfax O'Flaherty later set July 6 for a grand jury hearing and revoked Steeves' $50,000 bond, ordered earlier by Judge Robert Colby. Steeves, who has been jailed since his arrest, is a suspect in five other shootings on the same night, according to Alexandria prosecutor John Kloch.

In his testimony, Cebulski said Steeves had left home in Cebulski's brown pickup truck at 7:30 on the night of the shootings, saying he was going to visit his girlfriend. Cebulski said he was handcuffed and searched the next day by Alexandria police after they determined that a truck seen at the site of a least one of the shooting incidents belonged to him.

Cebulski added that while authorities were at his house, Steeves called him on the telephone from his girlfriend's home, saying he was thinking of fleeing, but finally resolving to surrender.

Kloch yesterday introduced into evidence the .44-caliber Remington magnum and the bullet allegedly used in the Montecalvo shooting.Steeves, who had been doodling with a pen at the defense table, bowed his head with a look of anguish as the prosecutor produced the bullet.

Claire Hunt, Montecalvo's roommate and a passenger in her car that night, testified in barely audible tones that she and the victim were returning home from the Grosvenor Riverside apartments shortly after midnight when the shooting occurred.

Under questioning from both Kloch and defense attorney Alfred Swersky, Hunt said she had been resting in the car with her eyes closed and had not seen where the bullet came from, nor had she seen a vehicle from which the shot could have originated.

District police hve said they are investigating similar shooting incidents that occurred between 12:30 and 12:50 a.m. the same night. In one case, a shot was fired through the passenger-side window of a car at I-295 and Howard Road SE, Det. David Israel said. The driver was unhurt.

Two previously reported shootings involved Donald Gee of Stafford County, Va., on I-295 near the Maryland line and Marc Gerald Muntz on the Woodrow Wilson Bridge. Gee escaped injury, but Muntz is still hospitalized for a back wound.

Arlington police also are investigating a shooting in the 1400 block of Jefferson Davis Highway in which a car was struck by a bullet. The driver was not injured.

The sixth incident involved a car that was struck by a bullet on the Southwest Freeway at Sixth Street. Again the driver was not injured, according to Det. Ruben Rodriguez.