Two more of the five persons killed in what police have described as a drug-related shooting Friday night in a Landover apartment have been identified as New York men, one of them a partly paralyzed native of Jamaica known by the nickname "Chief," Prince George's County police sources said yesterday.

The full names of the two men have not been released because relatives had not been notified of their deaths, police said.

Earlier, police identified two other victims of the multiple slayings as Everton Mitchell, 21, of the Bronx, N.Y., and Lloyd G. (Donnie) Chambers, 34, of Landover. Police still have not identified a woman who also died in the shootings.

Another woman who survived the slaughter with a gunshot wound in the neck remained in serious condition at Prince George's Hospital Center, police said. After undergoing surgery twice since late Friday night, the woman -- whose name has not been released -- talked to investigators yesterday about the shootings.

But police said the information she provided has not led them to a specific motive for the slayings, the largest drug-related incident of its kind in the county police department's 50-year history.

Police have tied the homicides to the escalating violence associated with out-of-town drug dealers -- many of them from New York and Miami -- who have invaded the Washington area in recent years to stake out what has become a lucrative market for illegal drug sales.

Many of the out-of-town drug dealers are natives of Jamaica who operate in loosely organized groups called posses. Their trademark, according to law enforcement authorities, is violence -- often dispensed with semiautomatic and automatic weapons. In the Landover shootings, three of the five victims have been identified by police or relatives as natives of Jamaica.

"They don't mess around," said Maj. James Ross of the department's Criminal Investigations Division. "If you steal their drugs or hold back on their money, they go after you."

To determine a specific motive, Ross said, investigators are gathering information about the four victims who have been identified. By trading and comparing information with other police departments -- including the District's -- detectives hope to learn about the victims' friends, relatives and business associations.

The victim known to police and Chambers' relatives as "Chief" is the same man who was wounded five years ago in a drug-related shooting in New York City, county police sources said. Since the shooting, police said, "Chief" had used a wheelchair.

One theory investigators are exploring, police sources said, is that "Chief" might have been a high-ranking member of a posse that had some type of dispute with a rival posse. "We've got to go back to them several times," Ross said. "They are not always cooperative. And sometimes, they might not even know the people we're asking about by the same name."

Assistant State's Attorney Thomas McManus, who has been advising the police department in the investigation, said his office has offered to subpoena any reluctant witnesses before a grand jury, where they could be forced to testify or face being sent to jail for contempt of court.

One of the two victims whose names have been released by police had an arrest record in Prince George's County, authorities said.

Chambers, whose brother had been deported to Jamaica because of what relatives called "legal problems" associated with illegal drugs, was charged with assault with intent to murder last July after he allegedly beat his estranged girlfriend, Vera Michelle Miller, and fired a weapon at her. The charge was dismissed last October, with no explanation in the District Court files.