Three men were found shot to death early yesterday in a Northwest Washington row house near Howard University in what appears to be a multiple drug-related slaying, according to District police.

The bodies of Robert Cooper, 43, of 60 Adams St. NW, and his brother, George Cooper, 60, were found face down in the kitchen and the dining room of Robert Cooper's two-story brick house, police said. Each had suffered multiple gunshot wounds in what police described as execution-style killings.

The third victim, who has not yet been identified by authorities, was also found in the house.

There have been no arrests in the case, according to police, and no motive has been clearly established. However, one officer said there are indications that the slayings may have been connected to illegal drug sales.

Residents of the area near the McMillan Reservoir have complained to police recently of an increase in drug trafficking in their neighborhood, particularly involving PCP.

Neighbors on Adams Sreet said the white Victorian-style row house in which the three men were found yesterday was known as "Mama Pearl's House."

Pearl Cooper, who lived in the house for many years, died last year, said Elsie Gates, 60, who lives at 56 Adams St.

"Mama Pearl was so sweet," said Gates. "She was everyone's grandmother. Everyone flocked around her."

"Bobby Cooper was nice," said Gates. "But after his mother died, he lost a lot of weight. He would come over here, and I would give him sandwiches."

Another neighbor, Laverne Bailey, 42 Adams St., described Robert Cooper as "just a nice man."George Cooper lived with his brother from time to time, police said.

Gates' daughter, Vanessa Gates, said she called the police about 7:15 a.m. after she heard loud noises at Cooper's house and thought someone was breaking in.

"There was so much noise that I went to the door to see if the police were there," said Vanessa Gates, 30, who lives in Oxon Hill and was visiting her mother at the time. "I thought someone was tearing down the bars on the window of that house. The police have raided that house before."

Gates said she had talked to George and Robert Cooper on her porch around 5:30 p.m. Friday.

Police Capt. Larry Soulsby said this is the first triple homicide in the District in several years. In April 1985, four persons were found shot to death in a Southeast apartment in what police said was the largest multiple homicide in the city in more than 12 years.

A source in the U.S. Park Police narcotics unit said yesterday that a search warrant was served by the Park Police at 60 Adams St. NW about six months ago.

Robert Cooper was arrested at the time and charged with possession of heroin with intent to distribute, the source said.

A quantity of heroin was seized at the house on Adams Street when the search was carried out and several other arrests were made in addition to Cooper, according to the Park Police source.