The two men had been drinking liquor and laughing by the curb Friday evening when their joviality turned suddenly, inexplicably, rancid. They began to argue. As neighbors congregated at apartment windows above the 3100 block of Buena Vista Ter. SE, they could hear the escalation of voices, but not what the dispute was about.

Then, in the haunting light of the night's full moon, hostile words turned to violence.

Sometimes in the heat of a city night, in streets where people live so close together that there is no escape from even the smallest affairs of their neighbors, a swirl of emotion can flare up like the sudden scowl of a summer thunderstorm and dissolve just as quickly, leaving irreversible damage in its peaceful wake.

And that's about as good an explanation as anybody seems to have for what went on with Allen Eugene Peterson, 33, and James Harris, 42, his next-door neighbor, Friday night.

The two men faced off, and after an exchange of obscenities, Harris walked angrily away. "I don't care if you try to stab me!" neighbors heard Peterson yell as Harris disappeared inside an apartment.

By now the children had been cleared off the streets and neighbors huddled in their windows, waiting to see if Harris would return.

Cleola Cooper, Peterson's aunt, said she had had a funny feeling about her nephew after gazing into the moonlit sky. Already that night, though unbeknownst to her, in the District alone there had been reports of a man shot in the back during a dice game; another man shot during an apparent drug deal; five people stabbed in unrelated incidents and two rapes.

Cooper recalled that she started to go to the window to call her nephew inside, then decided he was grown enough to take care of himself. But as she moved from her window and took a seat in front of her television set, she heard a loud blast.

"I heard my daughter scream," Cooper recalled. "She said, 'Mommy, Mr. Harris shot Eugene.' I ran to the window and what I saw, I can only call it dying."

"It was just stupid. It made no sense," another witness said. "One minute they were laughing and the next minute they were arguing."

The night had started off like any other on this street of low-income apartments where children and adults alike were enjoying the beginning of their weekend.

Harris had passed beneath Cooper's window and had asked her if she wanted to join him for a drink. "'I've already had five pints of whiskey and still have some left,' " she recalled him saying.

Cooper declined, deciding to watch the night's doings from her window for a change.

Peterson had been living with relatives in Washington for about five years, having come up from South Carolina for treatment of an acute alcohol problem. Earlier in the day he had suffered a seizure, but had bounced back for another drink, as usual, relatives said.

"He was real friendly, loved to clown -- especially sing and dance," Cooper said. "He never bothered anybody, although when he had been drinking he would ramble on and on."

Less was known about Harris, a tall and rather thin man who also liked to drink, it is said. As far as anyone knew, Harris and Peterson had never drunk together or exchanged words before.

But that all changed Friday night. A few minutes after his argument with Peterson, according to reports, Harris reappeared in the doorway of his apartment, motioning with his hand for a woman standing near Peterson to step back. Suddenly, Harris produced a shotgun and, from about 25 yards away, squeezed off a single shot, according to D.C. police reports.

"I saw Eugene hold his head, like he couldn't believe he had been shot," said one witness. "Then he just crumpled to the ground."

"His mother had begged him to stay home last night," Cooper said. "But Eugene said he just had to go outside. He laughed and told her to bring his insurance papers up to date. He sounded like death was upon him already."

Peterson was pronounced dead on arrival at the Greater Southeast Community Hospital early yesterday, and Harris was arrested and charged with murder, leaving neighbors to ponder the pool of blood that glistened in the light of the moon.