It was a long night of sudden violence and futile attempts to negotiate. Finally, flak-jacketed police stormed the smoldering Anacostia row house and found the sniper dead under a pile of fallen plaster, a shotgun and a hunting knife at his side.

The dramatic episode began at 7:45 p.m. Friday, police said, when one man was found stabbed and another shot near a house at 2106 Minnesota Ave. SE, and officers drew fire from inside while trying to rescue them. It ended quietly at dawn yesterday, as firefighters tossed buckets of debris from the second-story bedroom where a man identified by police sources and witnesses as Reginald Coleman, 33, had held authorities at bay for six hours.

Coleman, described by acquaintances as a troubled, despondent man, had written a will the morning of his death, a police official said. It was "absolutely suicide," the official said. "He . . . wanted the police to do it."

The stalemate between Coleman and the authorities was broken in a swift, massive display of force shortly before 2 a.m. yesterday. Under the cloak of a power blackout ordered by D.C. police, heavily armed Emergency Response Team officers assaulted the house aboard the city's new armored personnel carrier.

A lone officer stepped out of the squat vehicle and fired several shots into the first floor, according to witnesses. Other officers followed, firing tear gas canisters into the basement and second floor while firefighters trained their hoses on a fire that had erupted in the house.

After Coleman's body, clad in Army fatigues, was found on the second floor about 3:30 a.m., helmeted police filed out of the row house, their faces blackened with soot.

Police Chief Maurice T. Turner Jr. said Coleman started the fire. Tear gas was ruled out as a possible cause, he said, because it was used only after the fire had started to provide cover for firefighters working to prevent damage to adjacent buildings.

"Possibly the entire block" was endangered, according to Deputy Fire Chief Howard Dixon. Neighboring houses received slight water damage.

Coleman, who friends said was unemployed and attending vocational school, died of smoke inhalation and body burns, according to preliminary autopsy reports. The medical examiner's office has not determined if his death was a suicide.

His first victim, fellow roomer Donald G. Murriell, 42, was listed in critical condition at D.C. General Hospital with a shotgun wound to the abdomen. Lawrence Coleman, 45, a neighbor on the block who is not related to Reginald Coleman, was in good condition at Greater Southeast Community Hospital with two stab wounds received when he went to Murriell's aid.

City officials credited courage, armor and proper planning with averting a disaster.

"We don't have a Philadelphia here tonight," said City Council Chairman David Clarke, the highest-ranking elected official on the scene, in a reference to the catastrophic Philadelphia police assault on the radical group MOVE.

And Mayor Marion Barry sent a message yesterday congratulating police and firefighters for their performance in an "extremely tense and dangerous situation."

The fatal confrontation culminated a downward spiral in Coleman's fortunes, friends said.

JoAnne Jacobs, Coleman's landlord, said he was a "quiet man" who had been depressed for three months and became more despondent three days ago when police tagged his car to be towed.

Coleman had argued earlier in the week with his girfriend of five years, Regina Lanier, over his relationship with Jacobs, Lanier said minutes after learning of Coleman's death early yesterday.

Jacobs said, however, that there was no relationship between her and Coleman. She described herself as the girlfriend of Murriell, the man Coleman shot.

Lanier said early yesterday, "I don't even know what happened, if he flipped out or what. Whatever happened must have just balled up inside him and went off."

Coleman, she said, had bought a rifle about a year ago for target practice, but was a "kind, gentle" man who avoided fights, did not take drugs, and only drank an occasional beer.

"I'd be the one showing off all the time, ready to jump him, and he would just walk away," Lanier recalled.

Neighbors painted a different picture of Coleman, recalling frequent occasions when he fired guns into the air in a park across the street. "I've seen the dude," said next-door neighbor Michael Hill. "He'd get drunk and go out and shoot that gun in the air."

Ricky Banks, a resident of nearby 21st Place SE, also said Coleman liked to fire his weapon in the neighborhood. "He said, 'If the police ever come, I'm going to hold court out here in the street,' " Banks said.

A police official said Coleman, an Army veteran, had been seen in the neighborhood several days earlier wearing a "Rambo-style outfit." The official said a large ammunition belt was found on Coleman's body. In addition to the shotgun and the knife found near the body, a burned rifle was recovered that may have been used in the gunplay, police said.

Lanier said she had met Coleman when they worked together as clerks at the Immigration and Naturalization Service and he befriended her at lunch when coworkers ignored her. Coleman would take her to late-night movies, she said, and leave little notes with rhyming messages at her house.

She said she decided to call Coleman to try to patch things up between them about 8 p.m. Friday after not speaking to him for several days. When she telephoned his house, Lanier said, she heard only a recorded message that the phone was out of order.

A few hours later, Lanier received a call from a friend who told her a sniper was holed up in the house where Coleman lived.

The trouble began with an argument in the doorway of the house at 2106 Minnesota Ave. SE early in the evening, according to Joe Washington, a neighbor. About 20 minutes later, he said, he heard gunshots.

D.C. police, in their official statements yesterday, divulged few details of the incident, declining even to identify Reginald Coleman positively. However, a police official said that during the argument Coleman shot Murriell and that Lawrence Coleman went to his neighbor's aid and wrested the gun from Coleman. It was then, the official said, that Reginald Coleman lunged at Lawrence Coleman, stabbing him in the chest and taking the gun.

"Lawrence tried to help," said neighbor Hill, who witnessed the scene from behind a bush, "and that was when he got stabbed."

Lawrence Coleman's son, Brian, a Howard University student, said landlord Jacobs sought his father for help during the altercation.

When Lawrence Coleman arrived at the row house, his son said, "He was grabbed by Reggie and pulled into the house. He tried to talk to Reggie and he was stabbed in the chest. My father ran out of the house and Reggie pursued him with a rifle. All the police came and Reggie heard the sirens and reentered the house. My father fell on the sidewalk."

Brian Coleman, who said his father "always told me to extend yourself and to help others," was arrested during the siege after he crossed a police barricade to reach his home.

Authorities arrived at the scene about 7:45 p.m. to find Lawrence Coleman conscious and lying on the sidewalk a few houses away from the house where Reginald Coleman lived.

Fire Department Lt. Theodore Morris said authorities then heard an unidentified police captain shouting from the doorway of the house to a man inside, calling on him to throw out his gun. The captain shouted to the firefighters, telling them that a second victim, Murriell, lay in the doorway.

Grasping the man by his legs, the captain began dragging him from the doorway onto a small porch. Firefighters reached the porch and, while carrying Murriell back to their truck, heard two gunshots behind them. The standoff had begun.

An ambulance took Murriell away, while the firefighters remained trapped behind their parked fire truck for about 20 minutes until they were rescued by the armored personnel carrier, authorities said.

Between 70 and 90 neighborhood residents were evacuated to a neighboring elementary school, police said. Most were allowed to return home following the discovery of Coleman's body.

Police used a megaphone repeatedly to try to make contact with Coleman, who did not respond. He also failed to answer his telephone, police said.

Shortly after 11 p.m., police had Pepco workers cut power to the entire block. Police officials said they expected to "wait the man out."

Council Chairman Clarke said he happened on the sniper situation on his way to a meeting about a proposed homeless shelter in Anacostia.

About 12:45 a.m., Coleman started fires in two heaps of trash and was firing from the second floor window, according to police. Clarke said he saw police and firefighters marshaled together near the intersection of 22nd Street and Minnesota Avenue, where they donned bulletproof vests in preparation for approaching the house to fight the blaze.

"I was crouched around behind this car," Clarke said, pointing to an automobile at the corner of 22nd and Minnesota. "Fire and police officers boarded the armored personnel carrier. Then they went to the front side of the fire and boarded the fire engine there and aimed the hoses at the building while under fire from inside."

The council chairman described the subseqent taking of the building by Emergency Response Team officers after hoses were trained on the blaze and an exchange of gunfire had taken place between Coleman and police.

"There were no more shots," said Clarke. "They took the first floor firing automatic weapons. They fired tear gas into the basement and searched it. They then gassed the second floor and searched it and found the body."

Clarke, in addition to praising the efforts of the public safety officers, cited the city's fire code requirement of fire walls between row houses as a factor in restraining the fire and preventing major damage to adjacent structures.

Some neighbors criticized firefighters for reacting slowly to the blaze, but fire officials said they acted as quickly as possible.

Towana James Ramseur, a resident of the 1600 block of 21st Place, said she watched the fire from a vantage point east of Minnesota Avenue.

"I saw the fire start on the second floor and then they firefighters just waited and waited," she said. "They let it burn 15 to 20 minutes. The fire started in the left side of the front room and then moved to the right side."

Deputy Fire Chief Dixon said after police informed him of the fire in the building it took about 15 minutes to station firefighters in a position to train water on the blaze. In the interval, he said, "The fire had not progressed to a major proportion."

Dixon said that he, firefighter Richard Brown and police officer Michael Brooks donned flak jackets and were driven in the armored personnel carrier to a fire engine in front of the building, where they manned two water guns.

"It took us about 10 minutes to get a good, dark knock-down of the fire ," Dixon said. "My main concern was the fire extending to other buildings, but we stopped it almost immediately." He said that smoke in the second-floor window provided cover, enabling other firefighters to assist in dousing the blaze despite occasional gunfire.

The last volley came from the house about 1:40 a.m. Almost two hours passed before police discovered the body in the smoldering building, ending speculation that Coleman might have escaped across the rooftops.

Within minutes, the power was restored, lights flicked on and the rousted residents and curious onlookers converged at the corner of 22nd and Minnesota, which was as close to the crime scene as police would allow them.

Among those in the crowd was Coleman's girlfriend, Lanier.

"I knew he was living in that house, and I wondered, was he hurt?" she said.

Shortly before 4 a.m., a friend told her the name of the dead man. "No, Reggie," she moaned. Then she stumbled down the street away from the crowd and the flashing red lights.