Two 19-year-olds were arrested yesterday in connection with the Fourth of July slaying of a Silver Spring college student killed after a man posing as a letter carrier rang his doorbell.

According to court documents, at least one of the suspects arrested by Montgomery County police may be linked to similar "mailman" robberies in Prince George's County that occurred less than 10 days before the Silver Spring homicide.

Also yesterday, Montgomery County police issued an arrest warrant for a third suspect in the July 4 slaying of Anthony F. Williams, a 20-year-old Montgomery College student who was fatally shot during a struggle with the armed robbers. Police have identified that suspect as Earl Whittley Davis, 20, of Northeast Washington.

The two men now in custody on murder and attempted robbery charges in Williams's death are Adrian M. Brockenberry of, the 1300 block of Harvard Street NW, and Kodie C. Kinzer, of the unit block of Pennydog Court, Silver Spring. They are being held without bond in the Montgomery County jail in Rockville, Montgomery County police spokesman George Ludington said.

Kinzer turned himself in yesterday morning at the Silver Spring police station, Ludington said.

Brockenberry, who allegedly was dressed as a letter carrier at the time of the killing, was arrested late Wednesday at the D.C. jail on a fugitive warrant from Prince George's County, a D.C. police spokesman said.

According to charges filed yesterday, Brockenberry had been arrested in the District on automobile theft and cocaine charges, and in Montgomery County on charges of cocaine possession and distribution.

Williams was shot once in the abdomen around 10:15 a.m. at his town house in the 2400 block of Michigan Avenue, police said. He was awakened by his doorbell and by what court documents call "an unfamiliar male voice" stating, "You have a package." Williams asked, "Do I have to sign for it?"

According to police, Williams opened the door and three men forced their way inside. Brockenberry then allegedly asked Williams, "Where's the money?"

At the same time, Williams grappled with another suspect armed with a semiautomatic weapon resembling an Uzi, court papers said. The suspect then allegedly shot and killed Williams and kicked him "in the back several times."

Williams's cousin, who had been asleep on a couch, was then confronted by the robbers, who ransacked the house, court documents said. As the robbers fled, Brockenberry "approached the witness with the revolver extended, pointed at the witness's head," but was dissuaded from firing by another suspect, the statement said.

Brockenberry may be linked to June 25 and July 2 robberies in Prince George's County, police said, where an armed gunman used a similar "mailman" scheme.

Police allegedly identified Brockenberry from fingerprints taken from a phony package used in a Prince George's robbery.