Riot Police on Guard as Bensonhurst Juries Deliberate : Race relations: Murder case shows how anxiety racks New York. Mayor Dinkins is sharply criticized for inaction.

A large contingent of riot-helmeted police guarded the courthouse Thursday where twin juries were considering the fates of two white 19-year-olds accused of playing a principal part in the killing of a black teen-ager in the predominantly white Brooklyn neighborhood of Bensonhurst.

The presence of the police underscored not only the explosive potential of the case, but also racial anxiety in the city.

As both juries asked for portions of testimony to be read back to them, another judge in the same courthouse sharply criticized Mayor David N. Dinkins for failing to “personally intervene” in a bitter dispute between black protesters and Korean-American grocers in another Brooklyn neighborhood.

This dispute, coupled with the Bensonhurst case, has created the most serious problem in race relations so far for Dinkins, who was elected New York’s first black mayor on a platform stressing his ability to bring about a gentler racial climate in the city.

In an effort to diffuse tension and make his positions clear, Dinkins announced Thursday he would deliver a major address on racial problems.

“I think that we are doing pretty well with respect to race relations,” Dinkins said Thursday. “. . . I want to try to put things in perspective. I don’t mean to say I am unconcerned, that things are all rosy in our town. They have never been.”

The murder of the black teen-ager as he walked with friends last Aug. 23 sparked street protests and was a racial flash point in the bitter primary contest between former Mayor Edward I. Koch and Dinkins.

It was the third full day of deliberations in the case of Joseph Fama, accused of killing Yusuf Hawkins, 16, with a .32-caliber pistol. A separate jury worked for the second day, considering accusations against Keith Mondello, who prosecutors claim organized a group of whites carrying bats who surrounded Hawkins and three companions who had entered the neighborhood to look at a used car.

Each defendant faces 25 years to life if convicted of murder.

In contrast to Wednesday, when demonstrators calling for convictions of both youths punched Mondello’s lawyer Stephen Murphy as he went to lunch outside the courthouse, the scene was quiet on Thursday. Only a handful of demonstrators showed up in a pelting rain.

Meanwhile, the dispute over whether a Korean-American grocer or a black customer was at fault in a scuffle at the store has escalated into a boycott by black protesters of two Korean American-run groceries in Brooklyn’s Flatbush section.

State Supreme Court Justice Gerald Held, hearing legal arguments in the grocery boycott, urged both sides to attempt mediation. He said demonstrations could take place, but no closer than 50 feet from each grocery.

At the same time, he took Dinkins to task.

“The court regrets the failure of the mayor of the city of New York to personally intervene and use the prestige of his office and his high standing in the community to convince the parties to bring a suitable end to this dispute,” Held said.

Responding to earlier criticism, Dinkins has claimed that both sides in the dispute were close to a settlement before media attention began and the number of pickets outside the stores grew dramatically.

The mayor has tried to resolve the grocery boycott through quiet negotiations by his aides--a style that has brought him criticism from Koch and from the New York Times, which editorially prodded him for not acting more forcefully.

Noting that the mayor had appointed the deputy mayor to try to resolve the dispute, the Times nevertheless asked: “Is that all Mayor Dinkins can think to do? Racist fires are alight. . . .The boycott rides on a tide of ugly, unmistakably racist rhetoric that warrants condemnation from every fair-minded New Yorker, starting with Mayor David Dinkins.”

In a television interview, Koch declared that as mayor he would have gone down to the grocery and bought provisions for Gracie Mansion, the mayor’s official residence, to show his support.

The dispute began in January when a Haitian customer complained she was beaten without provocation by the store’s employees. The store’s owner countered by charging that the woman refused to pay the full price for her groceries and had to be restrained.

One of the store’s employees was charged with assault, and the case is being handled by the Brooklyn District Attorney’s Office.

The situation simmered until Robert C. (Sonny) Carson became one of the boycott’s leaders. Carson, a convicted kidnaper, received $9,500 from Dinkins’ mayoral campaign in what campaign officials described as part of a get-out-the-vote drive in the Democratic primary.

Later, during the election, Dinkins disavowed Carson, who had proclaimed he was anti-white. But the campaign never produced complete receipts for Carson’s expenses, and the fact it dealt with Carson at all disturbed some voters.

In its editorial, the Times acknowledged the facts in the grocery store dispute may be ambiguous. But it said there was nothing ambiguous about Carson’s behavior, calling him a “racial provocateur” and noting that leaflets handed out by pickets urged people to “boycott all Korean stores” and not to shop “with people who do not look like us.”