A U.S. Capitol police officer on his way to work shot and killed one man and seriously wounded two others during a melee that followed a minor traffic accident on Branch Avenue Tuesday night, Prince George's County police said.

County investigators said Officer Douglas K. Reardon, 26, a two-year veteran of the Capitol police, was driving on Branch Avenue near the exit ramp from the Capital Beltway about 10:30 p.m. when the rear of his car was struck by a pickup truck that was dodging in and out of traffic along with a van.

The vehicles stopped, police said, and, during an argument between Reardon and the occupants of the truck and the van, one man tried to take the officer's gun from his holster while two others began kicking him and pulling his hair.

Reardon, who had been wrestled to the ground, managed to free his revolver and fire, shooting a man who was on top of him, later identified as Charles E. Helms, 33, of Charlotte, N.C. Reardon then shot two other men, identified as Linwood Leroy Baker Jr., 31, also of Charlotte, and Donald E. Kelly, 27, of the 6400 block of Livingston Road, Oxon Hill, police said.

Helms was dead on arrival at Prince George's General Hospital, where Kelly was listed in critical but stable condition. Baker was flown to the Medstar unit at the Washington Hospital Center where he was listed in critical but stable condition. Capitol police said that Reardon received some scrapes and bruises.

Reardon, who patrols the Senate office buildings, was placed on administrative leave until county police complete their investigation.

Both Baker and Helms were known to be associated with the Hell's Angels motorcycle gang, according to North Carolina police officials.

Prince George's police said Baker and Helms, who work for a Charlotte firm, had been installing cable television equipment in the Forestville area Tuesday. They apparently met Kelly, a painter, on the job that day and they and some other associates then went to a Brandywine tavern.

County police said Reardon first spotted a green pickup truck and a van chasing each other and driving onto the shoulder of the road to pass other cars. Reardon's car was struck in the rear by the pickup truck, police said, and Reardon, the truck, the van and another car stopped.

U.S. Capitol Police said Reardon, dressed in civilian clothes, identifed himself as a police officer, and when the people who had gotten out of the other vehicles approached, he drew his service revolver and pointed it at the ground. When the group halted its advance, Reardon put his gun away and the melee ensued, police said. The last two men to arrive left the scene in their car before the fighting broke out, according to county police.