Prince George's County police have arrested a heavily armed man in Landover who told an investigator he planned to avenge his brother, one of five people killed Jan. 22 in an apparently drug-related slaying at a Landover apartment.

The arrest of Robert Clayton Williams, 25, the brother of 30-year-old Richard Alexander Williams, one of those killed in Landover, came to light a day after police identified three New York men as suspects.

Robert Clayton Williams, of no fixed address, was arrested last week in Landover on weapons charges after police received a tip that he was wanted on drug-related charges in New York, according to District Court documents and police sources.

Police arrested Williams about 11 a.m. Jan. 29 in front of 3510 Hubbard Rd., as he was entering a rented 1988 Buick Regal with Virginia tags, according to court records. When police searched Williams, the records said, officers found under his coat a .38-caliber revolver and two 9mm pistols, including one that had been converted to a fully automatic weapon.

Investigators had talked to Williams about the death of his brother and four other persons who were shot in the head and chest last month in an apartment at 2320 Brightseat Rd. Police sources said they believe Robert Clayton Williams might have been so heavily armed to protect himself or to avenge his brother's death.

Police issued arrest warrants on Thursday for Karl (Fabulous) Dunstrom, 27, Steve (Brown Man) McMillian, 24, and Kirk Bruce, 25, all from Brooklyn, N.Y. The warrants charge each man with five counts of first-degree murder.

Police have said that the Landover killings stemmed from the growing illegal drug trade in the Washington area, much of it spurred by an influx of dealers from New York and Florida, many of them natives of Jamaica. Although not all of the victims were involved in drug trafficking, police have identified all of the Landover shooting victims and suspects as Jamaicans.

The three suspects, according to sources in the New York City Police Department, had been arrested together there in 1986 on drug and weapons charges. Investigators in New York are looking for the men, the sources said, who frequented southern Brooklyn but also have used addresses in the Bronx, N.Y.

County police were led to the three men by a witness who was able to give detectives nicknames of some of the suspects, a county police source said. Investigators were able to match the nicknames with full names and pictures in the files of New York City police, the county police source said.

A witness later was able to identify pictures of at least two of the suspects, choosing their photographs from a series of six photos, according to county police sources and court documents.

Robert Clayton Williams, the brother of one of the slaying victims, also is wanted by law enforcement authorities in Georgia, according to court records. Williams was being held in the county jail in lieu of $25,000 bond.

Along with Williams' brother, Richard Alexander Williams, killed in the Landover apartment were Leonard Francis, 35, of Brooklyn; Lloyd G. (Donnie) Chambers, 34, of Landover; Everton Mitchell, 21, of the Bronx, and Carlene Cassandra Hamilton, 20, of Brooklyn.

Staff writer Victoria Churchville contributed to this report.