Two bank robbery suspects apparently killed themselves yesterday as Fairfax County police closed in on them minutes after the Central Fidelity Bank near Dulles International Airport was robbed, police said.

The two men, who law enforcement sources said were suspects in a series of bank robberies in Northern Virginia -- including one at the Central Fidelity Bank in January -- were found shot in the heads in a car parked in a church lot half a mile east of the bank in Chantilly, police said.

The two men had fled the bank wearing black ski masks and, according to a source, carrying $90,000 in two pillowcases.

After a brief chase, the men jumped from one getaway car and dashed to a car in the church lot.

The first officer to arrive called on the pair to halt, and one suspect fired a shot at the officer, police said. The officer fired two shots from his service revolver but missed, they said.

A second officer then arrived, calling over the patrol car loudspeaker for them to stop, and moments later shots were heard from the parked car, police said. Seeing no movement, the officers approached the vehicle and found the men with gunshot wounds in the head, they said.

Police and federal law enforcement sources said police believe that the suspects committed suicide based on gunpowder burns found on their bodies.

Fairfax police spokesman Warren Carmichael would not specifically confirm that account. However, he said police think suicide was the cause of death based "on the physical evidence that we've evaluated thus far {and} also by the fact that we are sure the two rounds fired by the officer didn't strike" the suspects. "Our investigators believe their wounds were self-inflicted," he added.

Another possibility police are considering is that one of the suspects killed the other before turning the gun on himself. Police said last night that they were still trying to positively identify the men. Carmichael said the suspects had Northern Virginia addresses but added that "doesn't necessarily mean they resided locally."

According to police, two men wearing black ski masks entered the bank at 14000 Sullyfield Cir., near Rte. 50 and Centreville Road, around 10:30 a.m. and ordered the bank's employes and three customers to lie face down on the floor.

One man, brandishing a gun, jumped over the counter and raided the tellers' drawers and the bank vault. The second man did not display a weapon.

The robbery took just minutes, and no one at the bank was harmed. The bank was closed for the rest of the day.

A spokeswoman for Central Fidelity would not comment on security arrangements at the Chantilly branch, and shaken employes were instructed by bank officials not to speak with reporters.

The spokeswoman said she expected the money to be returned but would not say how much was taken.

A passing motorist noticed the masked men and chased them, sounding his horn to alert a police car with flashing lights that was racing toward the bank in the other direction.

An alarm had been triggered at the bank at 10:37 a.m.

The motorist, who asked that his name and that of his passenger not be used, said: "I didn't exactly know what I was going to do. But I thought we'd follow them and get a license number."

The officer turned the police car around and began pursuit, which led to a gravel driveway adjacent to the parking lot of Ox Hill Baptist Church, just south of Rte. 50 in the Rockland Village subdivision.

The men jumped from their car, a black Ford Escort that police said had been stolen from a Maryland dealership, and ran about 15 yards through a stand of pine trees to a red Plymouth Gran Fury with D.C. tags in a corner of the parking lot.

Police said the men then jumped into the Plymouth, which they said had been left in the parking lot as an escape vehicle.

Just after they entered the second car, police said, the men apparently committed suicide.

"We heard something that sounded like firecrackers," said Bill Pevy, 52, pastor of Chantilly Wesleyan, just across the street from the Baptist church.

Police, who approached the car with revolvers and shotguns at the ready, according to one witness, found the men dead with gunshot wounds in their heads.

Also in the car were a .38-caliber Smith & Wesson handgun and a Ruger Mini-14, a semiautomatic rifle with a shortened stock.Staff writer Caryle Murphy contributed to this report.