Peggy Russell Gee, a top aide in District Mayor Marion Barry's reelection campaign, was slain and her house in Northeast Washington was set on fire early yesterday, D.C. police said.

The 55-year-old woman, who had scheduled Barry's campaign events, was found in the dining room of her house at 4209 18th St. NE after the fire department responded to a report of a fire there at about 5 a.m., according to a police spokesman. Police said there appeared to be forcible entry and the house was ransacked.

Gee was pronounced dead at the scene at 7:25 a.m.

"The fire has been ruled arson and the death a homicide," said Lt. William White III, spokesman for the police department.

Police would not disclose the apparent cause of death, saying that making it public might hamper their investigation.

Barry said yesterday that he had seen Gee on Friday to work out some scheduling details. Gee, a registered nurse, had worked in District government for about 16 years, running a city health clinic for some time, but had retired by 1979, the mayor recalled.

Barry said he met Gee when she was with the city government, and she worked in his first run for mayor in 1978 and again in 1982 as a top organizer in Ward 5, which includes the neighborhood where she lived.

"She was so enthusiastic . . . a very hard worker," Barry said. He said the mayor's command center called him about Gee at about 6:30 a.m. yesterday and the police briefed him later about the investigation, adding that he could not discuss an unsolved slaying.

Police spokesman White said there appeared to be no relationship between Gee's death and her position in the Barry campaign.

"She was one of the most decent people I know. I can't imagine her having any enemies," said Barry campaign spokesman Mary Braxton. "It sounds like a random burglary that turned into a homicide."

Gee, divorced and the mother of two adult children, had been involved in national politics, having worked on the presidential campaigns of Jesse Jackson and of former vice president Walter Mondale, Braxton said.

Longtime neighbor Josephine Johnson said that Gee had lived in the two-story red-brick house, in a quiet neighborhood of upper Northeast not far from the Maryland line, for more than 20 years.

Gee's home was burglarized about a year ago, and several other burglaries -- one across the street and one next door to Gee -- have occurred in the past two years, Johnson added.

"We have complained about the police protection," said Johnson, who has taken precautions that include installing bars on her windows and is now considering a spotlight.

Johnson described Gee as friendly but quiet and said their children had grown up together. "I just can't get it through my skull" about Gee's death, she said.

Johnson recalled how neighbors had worried about Gee earlier this year when she had been struck by lightning in front of her house but managed to crawl to a neighbor's house for help.

Another neighbor said she saw Gee's car parked out front and a light on in the dining room about 9:30 p.m. Friday but heard nothing until the fire engines arrived yesterday morning.

"I was really shocked. She has a dog, and usually I hear the dog barking when anybody is around, but I didn't this time," said next-door neighbor Gertrude Johnson.

Neighbors said Gee had lived alone since her grown children moved away.