Early March 13, a black man was found dead here near the subway tracks in the predominantly white, Roman Catholic neighborhood of Savin Hill. His skull was fractured.

Half an hour earlier, a gang of white teen-agers had chased him and a white companion into the subway station, hurling bottles and stones and racial insults.

In the wake of the death of 30-year-old William (Frankie) Atkinson, five Savin Hill teen-agers have been arrested and charged with manslaughter. One of them had attacked two blacks in the same station last April and received a suspended jail sentence for assault and battery.

Boston is unique in the annals of the nation's race relations. If the racial climate in other large cities is unstable from time to time, Boston's is consistently tense. A resistant strain of hatred grotesquely marks the city.

And Atkinson's death has aggravated the condition. Black leaders have stepped up their speech-making; black and white clergy have led 700 protesters into Savin Hill, and city hall is trying to convince the city that it was another isolated incident.

For many, especially blacks, Frankie Atkinson's death is just another of the ugly racial confrontations that have plagued Boston, especially since the start of court-ordered school busing eight years ago.

In the past two months alone: riot police were called into a racially mixed part of the city after about 100 young blacks began to stone whites in cars leaving a basketball game; a white man was pulled from his car in a black neighborhood and beaten senseless the night before his wedding; there were serious racial confrontations at two high schools after students came armed with clubs and chains, and a race-related stabbing in a third Boston high school.

Officials who have long dealt with the situation here believe Boston is suffering from one of the worst racial problems in the country, if only because the racial hatred has such a long history and is so easily accepted by the community.

Bruce Bolling, elected last year as the first black on the city council in 10 years, calls Boston's racism a "monster that's always around."

"Sometimes it sleeps, but then the dragon comes out and consumes someone else," he said. "We need a dragon slayer in Boston."

Boston likes to think of itself as the Athens of America, a mecca of cultural, educational and medical institutions. But it is also a city where blacks are afraid to go to professional sporting events because of the likelihood of confrontations, either inside Fenway Park where the Red Sox play and or in the North End neighborhood that surrounds the Boston Garden where the Celtics and Bruins play.

An entire generation of black youngsters is being denied the thrill of the city's sporting events because their parents fear for their safety.

There are entire neighborhoods--Savin Hill, South Boston, Charlestown, Hyde Park and East Boston among them--where blacks can go only at great personal risk. And many whites claim it is just as dangerous for them to go into Roxbury, parts of Dorchester and other black areas. Name-calling and racial slurs--shouted from passing cars or inscribed on the sides of buildings--are common here.

The situation has not been helped by an investigation of Atkinson's death that has raised as many questions as it has answered and has left his family accusing Boston of a cover-up.

Frankie Atkinson spent most of the evening of March 12, a Friday , at his brother's apartment on the outskirts of Savin Hill, drinking beer and watching the Celtics on television. With him was his friend William Grady, a 24-year-old white man who lives in the area with his mother.

Savin Hill, one of Boston's oldest neighborhoods, is divided into two parts. One is a small, peaceful, white working-class enclave, cut off geographically from the rest of the city by two major expressways and Dorchester Bay.

The houses, many of them huge Victorians, surround a park of grass and glacial boulders that rises to provide one of the best views in the city.

Its racial isolation is telling in the remarks of a man who grew up there. He was in high school before he ever met a black or a Protestant, in college before he ever met a Jew.

"It's hard for an outsider to imagine the isolation," he said. "Back then, everyone was Irish, and they were suspicious of people who hadn't come over from the same village in Ireland."

Across a bridge that spans the subway tracks and the Southeast Expressway is the other side of Savin Hill, where Atkinson's brother and all five alleged assailants live. Bulldogs, a bar where many of the young whites hang out, and the entrance to the subway station where Atkinson died are by that bridge.

It is largely a neighborhood of down-at-the-heels, double- and triple-decker homes, of bars, fast food restaurants, small shops and boarded-up, abandoned buildings. A few unwelcome blacks have moved into the area.

It will be impossible to find out exactly what happened the night Atkinson died until the facts are presented in the courtroom. The following account represents information pieced together from interviews with Atkinson's family and local officials, court records and newspaper accounts.

Francine Atkinson, Frankie's twin, says her brother and his friend left the apartment around midnight and crossed the bridge on foot into the all-white section to visit a friend..

Atkinson was a small man, 5-feet-8 and 118 pounds. He held a maintenance job at a nursing home just north of Boston and lived with his mother, but liked to spend Friday nights with his brother, watching sports on television.

He and Grady reached the friend's house, walking past the young whites who congregate outside after the bar closes at midnight. When they came back out onto the street, a battered brown Buick full of young whites was waiting for them.

"They were calling him nigger this and nigger that, saying, 'We ought to kill that nigger,' " Francine Atkinson said Grady told her.

She says Grady tried to intercede, but the shouting continued, and the car followed as they walked quickly toward the bridge. When rocks and bottles began to fly, Atkinson and Grady ran into the subway station, asking the man in the fare collection booth to call the police, then ran down onto the platform.

The youths chased them. Atkinson leapt down onto the rails, four or five feet below the platform and ran. Grady was knocked unconscious near the stairway. What happened next varies according to account.

Atkinson was found by a subway motorman about 1 a.m. 1,700 feet south of the station. An autopsy determined that his jaw, nose and skull had been fractured.

The original police reports indicated that seven whites were involved, that several of them chased him down the platform while others waited for him on the tracks and that they beat Atkinson to death.

A week after the incident, five young men from Savin Hill, 17 to 19 years old, were arrested and charged with assault with a dangerous weapon. There was no explanation of what happened to the other two.

Ten days after Atkinson's death, Suffolk County District Attorney Newman Flanagan called a press conference to announce that Atkinson actually might have been killed by a subway train.

He speculated that Atkinson's head injuries could have been caused by a piece of metal protruding from the train. He said investigators had found traces of blood on the metal, but didn't know whether the blood type matched.

Flanagan said the motorman operating the southbound train at 12:30 that night had felt a "thud" in the area where Atkinson was found. He stopped but did not find anything.

Flanagan explained that the new information about the train had just come to light because the motorman had left for a week-long vacation just after the incident.

Flanagan also said that police had since found an unidentified teen-ager who was on the platform that night waiting for a northbound train to South Boston, another all-white enclave, who had witnessed the incident. He said she had told police the white assailants abandoned their pursuit of Atkinson after he jumped to the tracks.

Another bystander on the platform was attacked by the young men, apparently because he was wearing clothing similar to Grady's. He reportedly also leapt onto the tracks and hid under the platform for 40 minutes until the commotion ended.

On March 30, a grand jury handed up indictments charging the five white youths with manslaughter. Each was charged with three counts of assault with a dangerous weapon (rocks and bottles) against Atkinson, Grady and the man on the platform. The assault charge alone without an accompanying charge of battery means that the grand jury concluded the young men threw the objects but did not hit the intended victims. The only assault-and-battery charge was against the young man suspected of knocking out Grady.

Confusion over facts has led to charges of a cover-up, not only by the family, but also by black leaders and a group of white clergymen who issued a statement March 29 calling Flanagan's investigation a "white, racist cover-up."

The family lists several contradictions:

* Francine Atkinson says that when the family met with police detectives after her brother's death, they asked specifically if he had been hit by a train or if he had been electrocuted by the third rail on the subway tracks that supplies the power for the trains. They were assured he had not been hit or electrocuted.

The family believes that if he had been hit by a train, his injuries would have been more extensive.

"My brother Mark went to identify him," Francine Atkinson said. "He said his face was swollen, black and blue. He said they beat the hell out of him. . . . But there weren't marks any place else, and his neck wasn't broken."

* As for the blood on the train, she questions whether blood would still have been there when the motorman returned from vacation after nearly 10 days of rain and snow.

There was another puzzling complication with that theory, she said. Her brother was wearing a tight-fitting green and white wool hat that night. When the family got his belongings, they say there was only a small spot of blood on the hat.

* In his press conference, Flanagan said Atkinson was six feet tall, a height that would have put him in line with the metal part on the train that Flanagan says might have killed him. His twin says Atkinson was only 5 feet, 8 inches tall and would have had to jump to be hit in the way authorities say he was.

* Finally, the family asks why Frankie Atkinson would have risked the electrified third rail and run 1,700 feet down the tracks. Why he would not have had time to move out of the path, if he were not being pursued.

"I'm not saying there wasn't a train," Francine Atkinson said. "Maybe there was. Maybe he hit it somewhere other than the gate, maybe they pushed him into it, maybe he was already dead by the time the train got there.

"But I'm afraid they came up with the story of the train because Frankie was beaten so badly . . . to keep the city calm. I'm afraid the train is meant to pacify those who don't want to believe there could be such a brutal crime," she said.

"He's my other half," she continued. "I haven't cried yet. I don't know how I can live with this. I don't know what I'm going to do with the rest of my life."

Boston Mayor Kevin H. White did not have time for an interview on the city's racial problems. He is preparing for a month-long trip to China to visit Boston's sister city of Hangzhou.

He has released a written statement calling the killing "a savage, brutal, senseless act of violence."

Flanagan and Police Commissioner Joseph Jordan refused to discuss details of the case.

"The D.A. doesn't want to be in a position of having a case overturned because of the publicity," Jordan explained. He added that he thinks racial incidents in Boston are "increasing because it seems the media want to know everything."

Boston is a city of contradictions.

Some $1 billion in new development was undertaken here last year, and more than that is planned this year. Fancy hotels and restaurants are sprouting along the waterfront.

But in the neighborhoods, both black and white, few residents have seen the effects of that money.

The city's disadvantaged are locked in the low-income subsidized housing that is almost completely racially segregated. Blacks who have attempted to move into white housing projects have been consistently been driven out, generally by vandalism and firebombing.

Unlike some other parts of the country, families are still tightly knit in Boston's neighborhoods. Outsiders are spotted immediately and are often not welcome, white or black. There has been little real racial integration in the stable neighborhoods.

Houses are generally passed from generation to generation. When one is for sale, it is usually sold by word of mouth, not by realtor or newspaper ad.

The schools were also segregated until 1974 when Judge W. Arthur Garrity ordered the city to begin busing to achieve racial integration. There was immediate white flight to private and parochial schools, and since then, the white population in the public schools has dropped from 70 percent to 30 percent.

Martin A. Walsh, who has been in Boston since 1974 as part of the U.S. Justice Department's Community Relations Service, says, "There's a perception on both sides of a dual standard of justice, of the other side getting everything. If we don't deal with it, we just continue and reinforce a legacy of justification for racial problems."

Walsh does not blame any one person or institution for allowing the problems to continue. He blames everyone for not doing enough. Meanwhile, he worries about what will happen when warm weather brings young people out to spend their days on the streets.

Because of cutbacks in both city and federal funds, there will be only 2,100 city summer jobs this year--compared with 11,500 several years ago--for what the city estimates will be 30,000, 14- to 19-year-olds looking for work.

And because of city budget problems, more than 20 percent of the city police force has been laid off.

Walsh said that in Boston racial incidents tend to be spontaneous.

"That makes it worse, more deep-seated," he said. "When it happens spontaneously, it becomes part of the psyche, the mores of society. It's like living in a state of war."