A bank customer who was carrying a pistol was shot to death yesterday when he exchanged gunfire with a bank robber in an effort to foil the holdup of a downtown Washington bank.

A 22-year-old Washington man apparently wounded in the exchange, was arrested minutes later in connection with the robbery and shooting.

The shooting occurred shortly after 11 a.m. as the robber attempted to leave by the front door of the crowded First American Bank branch at 13th and G streets NW with a bag of money taken from a teller, D.C. Police said.

The customer, John David Bowen, 30, was making a deposit for a nearby florist shop at the time. Bowen, who had been robbed and beaten by attackers in the area twice this year, apparently realized that a robbery had occurred and raced the robber to the door.

There, both men exchanged shots and fell to the ground. The robber struggled to his feet, emptied his pistol into Bowen as he lay on the floor, then ran into the street, police said.

The bag of money -- which contained a small canister of red dye placed there by the teller -- exploded at that point, scattering banded stacks of $5 and $10 bills across the sidewalk and into the street. Within moments, 50 to 100 pedestrians were scrambling to collect the bills, police said.

One man, who was driving by the bank at the time, stopped his van, opened his door and scooped up a handful of cash before quickly driving off. Police issued an all-points lookout for the van but as of last night had made no arrests.

Nonetheless, most of the money was recovered, police said. Officals would not specify the total amount involved.

The suspect was arrested in an alley adjacent to the bank. He was identified by police as David Wayne Basnight of 4046 Gault Pl. NE. He was being held in the D.C. Jail, where he was listed in good condition with a jaw fracture apparently caused by a bullet wound to the chin, police said.

According to authorities, the robbery began when a man entered the bank and pushed to the front of the line of waiting customers. A teller asked the man to step to the rear of the line but the man refused, police said.

"He opened his trenchcoat and showed the teller a gun," a police official said. "Then he said, 'Lady, I don't have to wait for anybody.'"

The robber placed a note, which read "I want it all or I'll kill you" in front of the teller along with a bag.

"You do this," police quoted him as ordering the teller. When the teller started to hand the half-filled bag back to him, he told her, "I want all of it."

She then filled the bag and dropped in the explosive canister.

The robber turned to flee, but Bowen was just ahead of him, police said. The two men confronted each other in the foyer of the bank building. Both were felled in the exchange of shots, but only the robber got up again.

Witnesses told police that the robber then fired four shots at point-blank range into Bowen's prone figure before turning to flee.

Bowen, an employe of the McCallum Sauber florist wholesalers at 1314 I St. NW, was making the Monday morning deposit for the company at the time.

"I tried to warn him against working in the area where he was," Bowen's mother, Mary Ann Bowen, said last night. "I think it's a bad area. He'd been attacked twice already.

According to his mother, Bowen, who was a divorced father of two and had lived with his parents for the last two months, was first attacked earlier this summer by five youths who had beaten him to the ground, causing a concussion.

"I think they took his wallet and his jacket," she said. "But I think he got up and chased them and got his wallet back."

About two months ago he was attacked again, she said.

"I didn't know about it until today," Bowen's mother said. "My daughter told me. He didn't want me to know because he knew how much I worried. He had a broken rib and had 22 stitches in his chin, and he grew a beard so I wouldn't see the scar. I told him just yesterday that I liked his beard. He said he grew it to hide the scar, but he didn't tell me how he got it.

"Maybe that's why he had the gun, if he had one," she added. "We never knew he had one. I just know that he worked very hard for a living. He worked two jobs in order to support his children, long hours in all kinds of weather. I think he did it because he felt you had to help people. People have to help each other instead of just standing by."

"He cared about the people he worked with," Bowen's sister said. "He always cared about the underdog."

Bowen's employer, George F. Abdow, said: "I told him if anyone bothers you, let them have [the money]. I told him his life is worth more than the money."

According to Abdow, the owner of the florist shop, another employe was robbed on his way to make the deposit just five weeks ago.

There was no information available as to where Bowen obtained the .22-caliber pistol he was carrying at the time or whether it was registered.