Four young men have been arrested in connection with last week's daring daylight robbery of a Brinks armored truck at Dulles International Airport, authorities announced yesterday.

All four men, who range in age from 18 to 21, were arrested Friday night and arraigned yesterday morning in D.C. Superior Court on charges of conspiracy and interference with commerce, according to the FBI. The suspects were being held without bond last night at D.C. Jail, according to an official there.

The robbery occurred about 6:40 a.m. Wednesday at a Federal Express cargo bay at Dulles airport when as many as five men disarmed and injured two Brinks guards and made off with two canvas money bags containing more than $100,000 in cash and documents.

A fifth suspect may still be at large; a statement released by the FBI yesterday said the investigation is continuing, with "additional arrests anticipated."

Those arrested, according to the FBI statement, were Kevin Tyrone Baldwin, 21, of the 1300 block of Fifth Street NW; Albert Larry Weaver, 20, of a different apartment at the same address; and Kirk Douglas Greene, 19, and Rudolph Hilton Williams, 18, both with no known address.

If convicted, each of the four could face up to 25 years in prison and $500,000 in fines.

An FBI spokesman declined to reveal such details as whether the money was recovered, where and when the arrests were made, what role any of the suspects was alleged to have played in the robbery or how agents and detectives concluded that they were allegedly responsible.

David A. Varrelman, chief of the Metropolitan Washington Airports Authority Police Department, which assisted in the investigation, said none of the suspects was an employee of the airport, an airline, Federal Express or in any other way associated with Dulles. He said no one noticed anyone casing out the area in the weeks leading up to the robbery.

Varrelman said investigators had targeted specific suspects by Wednesday night and spent the next several days gathering evidence before seeking arrest warrants. He would not say how investigators identified the suspects, attributing it simply to "good, hard detective work."

The getaway van with District license tags was recovered Friday morning at or near Dulles airport, Varrelman said.

Varrelman also said he did not believe that the stolen bags have been recovered yet. Authorities have not disclosed specifically what was stolen, saying only that it may have been a combination of cash, non-negotiable financial documents and other items, possibly including jewelry, and that $100,000 was a "very conservative" estimate of the value.

"I'm not sure if we've even determined what was in the bags," Varrelman said.

Neither law enforcement officials nor Federal Express representatives have revealed the source or intended destination of the stolen shipment.

The incident occurred after the armored car backed up to the Federal Express loading dock on the street side of cargo bay 90. As many as five men, several of whom brandished weapons, encountered the guards, took their .38-caliber handguns and attacked them while a third guard sat apparently unaware in the driver's seat.

The injured guards were treated for minor injuries to the head, chest and neck.