It started three years ago as a fight between two neighborhood dogs. When it ended Tuesday night, six people who had been involved in one way or another had been shot, two of them -- the owners of the dogs -- fatally.

Police investigators said the man who was responsible for the shootings in the solidly middleclass neighborhood of long-time residents was one of those killed. He was Carroll T. Fleet, a 56-year-old Navy Department civil engineer who told a neighbor before the shooting began that "enough is enough."

"A man has his limits," Fleet was quoted as saying before he stepped out of the home he had occupied for 17 years. "I'm 56 today, and I can live with the consequences." Then, police said, Fleet produced a.38-caliber revolver and declared, "Everybody's going to die today." They said Fleet died of a self-inflicted wound.

The feud started when a collie owned by Betty Haney, a 57-year-old social worker, reportedly attacked Fleet's German shepherd during a stroll three years ago.

Neighbors said Fleet complained to police about unleashed dogs several times. They said Fleet became irate when the Haney dog would foul his lawn. When he continued complaining, Haney's 16-year-old daughter, Marla, began calling him "a freak," neighbors said.

"I've been knowing him 17 years and he never dipped into nobody's business and he detested people dipping into his," said Noble Hampton, who lives across the street from Fleet's home. "The kids would curse him, throw cherry bombs in his yard. But he'd stay calm. He had over three years of that pent up inside. It all grew out of these dogs. It's been ill feeling for years."

Neighbors said Fleet also had been involved in an argument with Leroy Williams and his son, Leroy Jr., who live at 5609 First St. NE. The argument centered on Leroy's treatment of Fleet's dog, neighbors said, and came after the original fight.

When the Williamses and a friend, Everette Davis Jr., 20, returned from grocery shopping Tuesday evening, they were met by Fleet, who began firing at them from point blank range, police said.

The elder Williams, 62, was shot in the chest and was listed in critical condition at Washington Hospital Center.His 20-year-old son was hit in the arm and was listed in good condition at the Center. Davis was struck under the chin and also was listed in good condition.

After reloading, police said, Fleet went next door to the Haney residence, smashed the glass storm door and began punding on the main door. Mrs. Haney opened it and was shot in the chest. She was killed instantly, police said.

Then Fleet went upstairs, shot and killed the Haney's dog. Marla Haney, 16, was shot once in the head and twice in the chest while her sister, Kimberly, 15, hid in a closet. Marla Haney was listed in critical condition yesterday at the Center.

Fleet then shot himself to death.

The teachers, research analysts and civil servants who live in this black middle-class neighborhood expressed shock at the shootings. Few, however, would talk for attribution about the incident or the people involved.

"This is a closed in, quiet, mind-your-own-business neighborhood," said the historian who lives on the block. "Middle America right here on First Street. I'm afraid we're likely to see more of this kind of thing as people realize that the American dream is a myth."

According to Hampton and others, Fleet began his Tuesday by shoveling his driveway, then going from house to house, helping others remove snow from the street.

One neighbor said she found Fleet "unusually pleasant," Tuesday. "He never used to say much, just talk generally," she said. "But for some reason he started talking about his childhood, growing up as a boy in Georgetown." Fleet was born in Washington.

Neighbors said that Fleet often was taunted by children because he was a very fair skinned black. "It incensed him that the young ones would call him names like 'freak,'" one neighbor said.

"He would often say that he liked children, but he couldn't stand how they disrespected adults. He couldn't understand how young girls could use [profane] lagnuage," a neighbor said.

Fleet, who had no children, had owned two dogs. One died several years ago. "He was very fond of the dog. He walked it every day. You could also count on Mr. Fleet making his rounds," a neighbor said. "Just saying hello or goodbye, smoking his pipe, walking his dog."

Fleet is survived by his wife.