The scene is a crowded South Boston Street. Hundreds of whites, angered by court-ordered school busing, mill about in front of a ramshackle high school building. Television cameras follow the tall, tousle-haired man with rugged good looks who is this city's police commissioner as he keeps both angry demonstrators.

The image is clear even today, two years after Robert J. diGrazia won his national reputation as a tough, but innovative, enlightened, and likable policeman.Clear, that is, everywhere else but in the city of Boston.

For since diGrazia left in November to become chief of Montgomery County's 784-member police force at $10,000-a-year salary increase, Boston's news media have reported that diGrazia failed to act against the police corruption; officials of the policemen's union have accused him of trying to destroy their organization; his personal life has been the subject of rumor; and he's been accused of leaving Boston in hopes of becoming the next chief of the FBI.

Montgomery County's hardly the center of action," said Boston City Councilman Lawrence S. DiCara, an acknowledged diGrazia supporter, expressing a widely-held view. "But it's next door to it."

"DiGrazia was a phony from the day he allegedly donned a uniform," said outspoken diGrazia critic Chester J. Broderick, chairman of the union which represents nearly all of the city's 2,038 patrolmen. "He was a dirty rotten, vicious man who supported people's civil rights only as long as they (the people) didn't work for him."

DiGrazia shrugs off the furor over his leaving and the criticism of his tenure. "I'm a big boy. I can take it," he said in a recent interview in his suburban Montgomery County apartment.

"I had three strikes against me from the beginning there," he said as he polished several pairs of shoes. "I was an outsider. I wasn't Irish in an Irish-dominated department. And I was talking reform."

There are those in Boston who agree.

"He was an enormously good force," and Barney Frank, a state legislator from Boston. "He really did care and he managed to convey that."

The most popular theory in Boston as to why diGrazia left is that he viewed the Montgomery post as a better stepping stone to the directorship of the FBI.

Those who espouse that theory discount his explanation that the Montgomery County police chief's annual pay of $46,524 - some $10,000 more than he earned as commissioner in Boston - was the major reason for his leaving Boston. DiGrazia had said he needed the larger salary to pay the tuition of three of his four children who attend college or private school.

But diGrazia emphatically denied that he has been secretly eyeing the FBI post.

"I haven't been contacted about it and I haven't initiated any contacts," he said flatly. He attributed the speculation to the "elitist" view he said many Bostonians have of their city.

"They think everybody wants to stay there forever. They can't believe somebody would leave, without a nefarious reason," he continued, adding that many probably consider the suburban Washington jurisdiction "a one-horse county with a single traffic light," although its population of 589,000 is only about 75,000 less than Boston's.

"I've got my eye set on Montgomery County," diGrazia said. "I liked what I saw. The pay was there. There're a lot of people with talent in the police department."

DiGrazia has been on the job here only a month, spending most of it meeting staff members and learning department operations. Known as a "radical innovator" for his reorganization efforts in Boston and St. Louis County, Mo., before that, he said that thus far he doesn't think many changes will be necessary here because the department is in "good shape."

DiGrazia, a ruggedly handsome and urbane man who at 6 feet 4 is both physically and personally imposing, presents vivid contrast to his traditionally staid, low-key predecessors.

"DiGrazia convinced people by his presence that things were changing in the police department, "Boston City Councilman Lawrence S. DiCara remarked. "He showed up at community meetings to talk to people about their crime problems, he invited citizens to come and see him, he told his people they had to be responsive and he transferred those who weren't."

The first career policemen to be the city's police commissioner (the job has been used as a political plum by either the Boston mayor of the Massachusetts governor), deGrazia was also the first commissioner in modern times who was not of Irish descent.

DiGrazia tells the story of his attending a testimonial dinner for a retiring police chaplain shortly before he took office.

"About 75 per cent of the policemen there were Irish, about 20 per cent were Italian, and they were split. The Italians were sitting over here and the Irish were sitting over there."

DiGrazia said he got only lukewarm applause from the Irish cops, but a standing ovation fromt their Italian counterparts. "It was the first time I noticed (the polarization within the department). It was that bad, really that bad."

However, his critics said diGrazia alienated many policemen with his outspokesnness about internal reform, his "heavy-handed" discipline, and his promoting some officers over others who ranked higher.

Several accused him of surrounding himself with a small group of young, intellectually liberal, civilian aides who had little actual police experience.

These aides, derisively called by diGrazia's critics the "whiz kids," were the focus of intense resentment among diGrazia's critics in and out of the department. They assert that diGarzia and his aides ignored the advice of the department's top uniformed officers, a charge diGrazia denies.

DiGrazia, 48, born in San Francisco, joined the police force in Novato, Calif., becoming chief of the 27-man force in 1963. In 1969 he took over the 660-member police department in St. Louis County, Mo. Boston mayor Kevin White named him the city's police commissioner in 1972.

DiGrazia became a popular social figure in Boston. He flaunted his Italo-American background, but also hobnobbed with Boston's social elite and several observers said, was as likely to be mentioned in society columns as in news reports.

DiGrazia was almost immediately confronted with controversy, however, when a raid on a bookie's home turned up a book allegedly listing the names of 58 policemen "on the take." Although the names in the book were never made public, DiGrazia forced the retirement of 11 police officers and disciplined others.

"That department needed to be turned around," he said between quick, vigorous passes at a shoe with a brush. "It was necessary to take some drastic action to let policemen and citizens know that something was gaong to be done abous an archaic, unprofessional, and self-serving organization. Some people didn't and still don't like that."

After the initial flurry of retirements and disciplinings, DiGrazia said he found himself confronted with foot-dragging and outright opposition within the department to further reform-minded moves.

One well-informed source said that DiGrazia, frustrated at his inability to push through significant reforms, began spending more and more time away from the department in 1974 as time drew near for the court-ordered busing to begin.

"He was taking whatever speaking engagements he could get," the source said. "(Mayor) White finally had to order him to stay (in Boston) to get ready for the busing.

DiGrazia denied the allegation. "Everybody (else) was in hiding," he said, while he was preparing almost alone to see that the order would be properly implemented.

Following the implimentation of the busing program in the highly charged atmosphere during which DiGrazia's coolness earned him high marks nationally, he made the decision to leave Boston.

So last month, less than a week before leaving Boston, he released a stunning, 572-page internal report that alleged that one entire police district was rife with corruption.

The report listed nearly 20 specific instances of illegal police conduct, but discussed them only in general terms and didn't identify individuals.

Shortly after the corruption report's release, diGrazia from Montgomery County, announced that he and his wife of 22 years were separating.

Coming after his surprise resignation (with a year left on a 5-year contract) and the corruption report, the separation announcement, one observer said, affected this conservative city like "a rabbit punch to an already reeling fighter."

"They're blowing in the wind with the political charges and counter-charges, but it's a way of life in big cities," said Charles Maier, aide to Montgomery County Executive James Gleason. "Front page stories about his marital separation, well, it's different here, it's not the same atmosphere, it's a smaller place."

It's also smaller police force, a force that Maier says appreciates what Boston police disliked. While the tradition-entrenched Boston force opposed change, the younger Montgomery County police are glad to be "woken up" by diGrazia, Maier said.

"I'll tell you though, the difference in personnel (from Boston) is just unbelievable. It's great to see the caliber of people in the department. I'm just really enthusiastic about what I see here," diGrazia said.