Three District residents were indicted yesterday on charges of robbing a Brink's armored car last month at Dulles International Airport, but charges against a fourth man arrested in the holdup were dropped and he was released.

Law enforcement officials said that those indicted in U.S. District Court in Alexandria are part of an organization called the Fifth and O Street Gang.

About $4 million worth of foreign currency, jewelry and nonnegotiable bonds was taken in the holdup at a cargo dock at the airport May 30. None of the stolen goods has been recovered, according to federal law enforcement sources.

The indictments against Kevin Tyrone Baldwin, 21, Albert Larry Weaver, 20, and Rudolph Hilton Williams, 18, charge them with using a weapon during the commission of a felony in addition to robbery.

Charges against Kirk Douglas Greene, 19, who had been arrested and jailed in connection with the case, were dropped and he was released after spending two weeks in jail.

Gregory B. English, an attorney for Williams, said Greene's release demonstrated that the government relied too heavily on anonymous phone tips and failed to fully investigate the robbery.

"The only evidence on {Greene} consisted of anonymous phone calls," English said last night. "They're not admissible as evidence. They're hearsay."

Prosecutors sought the indictment yesterday because federal law requires that defendants be indicted within 30 days of their appearance in the jurisdiction where they are to be prosecuted. The men were brought to Alexandria June 5, and no more federal grand juries were scheduled until the week beginning July 9.

"The availability of the grand jury dictated that we proceed at this time," said U.S. Attorney Henry E. Hudson. "Ideally, we would have liked to wait until a later time to finish the investigation of leads that are still outstanding."

Federal law allows the prosecutors to seek an indictment against Greene or other suspected conspirators at a later date. FBI Special Agent Howard W. Luker testified at a related detention hearing this month that "we feel there are at least five, maybe as many as eight" men involved in the robbery of the Brinks car.

Baldwin, Weaver and Williams face possible prison terms of up to 20 years on the robbery charges and a maximum of five more years for the gun charges. They will be arraigned July 2.

Yesterday's indictment alleged that Weaver and Williams robbed a Brinks armored car at about 6:40 a.m. as three guards were loading a shipment at a Federal Express cargo dock at Dulles.

Assistant U.S. Attorney W. Neil Hammerstrom Jr. told the court at a detention hearing this month that the guards were "struck with either weapons or hands -- in the head -- and forced into the truck."

Brinks guards identified Weaver and Williams from photographs provided by the FBI. Special agent Luker has testified that investigators were led to Baldwin and Greene by anonymous callers who accurately described in detail when the robbery took place, what was taken and where the getaway van could be located.

The indictment alleges that Baldwin provided the van, which was registered in his father's name.