Phillip Joseph Steeves, the 21-year-old Marine corporal accused in the sniper slaying of a young woman motorist in Alexandria and a suspect in two other shooting incidents early Wednesday, was ordered held without bond yesterday in the Alexandria city jail.

Steeves, who surrendered to Maryland State Police Wednesday evening at a Landover Hills service station, was handed over to Virginia authorities early yesterday after he waived extradition at a brief hearing in Prince George's County.

"He was extremely depressed," said General District Court Judge Graydon S. McKee, who talked to Steeves in his chambers in Upper Marlboro. "He said very little."

Police who interrogated Steeves for several hours at the Alexandria jail yesterday said the youthful looking Oregon native had refused to answer their questions. "He's acting like a real Marine," said Virginia trooper Mark Jones.

Steeves, who has hired Arlington attorney John E. Kilcarr, is scheduled to be arraigned on the murder charge at 9:30 a.m. today in General District Court in Alexandria.

Authorities said they had been unable to establish a motive for the slaying.

The victim, Mary Anne Montecalvo, 24, of Arlington was hot in the chest by a sniper police said had pulled alongside in a pickup truck as she and a friend drove home along North Henry Street about 12:30 a.m.

A witness' report of a Marine Corps decal on the truck led investigators to the Marine Barracks in Southeast Washington, where Steeves was assigned.

Alexandria law enforcement officers, who said they believe the slaying was related to two separate shooting incidents only minutes earlier, have placed no other charges against Steeves, they said.

Police said they did not believe Steeves was acquainted with any of the motorists involved in the incidents.

Marc Gerald Muntz, 28, of Alexandria, who was shot in the chest as he drove across the Woodrow Wilson Bridge about midnight, was listed in serious condition yesterday at Mount Vernon Hospital in Fairfax County. He was described as being in a semiconscious state and had not been questioned by police late yesterday.

A third driver, Donald Gee of Stafford County, told police his car had been fired upon as he drove on I-295 near the Maryland end of Wilson Bridge, but he was not hit.

Military personnel at the Marine Barracks and at Bolling Air Force Base where Steeves lived described him yesterday as pleasant, easy-going and somewhat reticent.

"This is just a big shock," said Capt. Mastin Robeson, the commander of the 18-member unit where Steeves served as a cafeteria worker for the Headquarters Company barracks.

The son of a telephone company repairman, Steeves, a clean-cut, sober-faced man, enlisted in the Marines three years ago, only days after he graduated from high school in Bandon-by-the-Sea, Ore. Military records show he received infantry training at Camp Pendleton, Calif., and had been stationed at the Marine Barracks at Eighth and I Streets SE since December 1978.

Police and Marine Corps officials said yesterday that Steeves has no criminal record and no apparent history of disciplinary problems during his service in the Marines.

Fellow Marines, several of whom said they were ordered by base officials not to discuss the incident with the press, said they knew of no reason for him to be involved in the shootings.

"We used to go to bars and drink and he never drank more than any of us and never got rowdy or anything," one said.

One source close to the investigation said yesterday that Steeves was possibly under the influence of drugs at the time of shootings.

Although Steeves was assigned a room at the barracks, he had recently begun sharing an apartment at the drab Bellevue housing quarters at Bolling in Southwest Washington, about two miles from the barracks.

Steeves lived there in violation of military policy, according to residents of Bellevue. The development is restricted to families, while single enlisted personnel like Steeves are required to live in the barracks.

"Bellevue residents said Steeves recently moved into a two-bedroom apartment occupied by Marine Cpl. Michael Cebulski, and Cebulski's wife and child.

Marine Cpl. Jim Lipsius, who lives several doors away from Cebulski, described Steeves as a good listener who rarely revealed much about himself or his past. "I would tell Steeves a lot of things about myself but I can't remember anything he said to me about himself."

A D.C. police official said yesterday that officers who searched Cebulski's apartment had seized several handguns, hand grenades, black powder and ammunition. The search was apparently conducted without a warrant because Cebulski agreed to cooperate with police.

Montgomery County authorities ruled out Steeves yesterday as a possible suspect in the wounding of an Oxon Hill man who was grazed by a bullet fired by an unknown assailant as he walked along a sidewalk in Silver Spring at mid-morning Wednesday.

That incident occurred about 10 hours after the death of Montecalvo. Police said that from what they could determine about Steeves' whereabouts, he could not have been involved.