The case of Terrance G. Johnson, the 15-year-old Bladensburg youth accused of killing two Prince George's County policemen, has become a subject of widespread interest and controversy even through the start of his trial is still at least a month away.

Johnson's mother, Helen, has joined with two members of Prince George's NAACP to start a defense fund and they have raised about $2,000 in two weeks from various groups.

County State's Attorney Arthur A. Marshall Jr. has decided to prosecute Johnson himself, the first case he has personally tried in 2 1/2 years.

In the meantime, members of the county police force have promised they will turn out en masse at the trial, hoping to see Johnson receive a maximum life sentence.

Members of the black community say they will also be at the trial to support Johnson and his family.

Thus the elements for a bitter and emotional trial are present in a county where relations between a 91 percent white police force and a rapidly growing black community have been uneasy for several years.

"It isn't that we're against the police or anything like that at all," said Carol Garvin, treasurer of the Johnson defense fund. "It's just that something like this was bound to happen sooner or later because of methods police here have been allowed to use for years.

"Terrance is going to plead not guilty and we believe that once all the evidence is aired, he will be found not guilty."

The two officers, Albert M. Claggett IV, 26, and James Brian Swart, 25, were both shot and killed the morning of June 26 in the processing room of the Hyattsville District police station.

The two officers had taken Johnson and his brother Melvin, 18, into custody shortly after 2 a.m. on suspicion of larceny.

At about 2:40 a.m., Claggett was preparing to fingerprint Terrance when the youth allegedly grabbed the officer's gun from his holster, shot Claggett, then shot Swart as he came running into the room.

Harvin, Eloise Hamilton and Helen Johnson, who are controlling the defense fund, have hired R. Kenneth Mundy, Joseph L. Gibson and Alan Lenchek to defend Johnson. The lawyers have already filed a motion requesting that Johnson be tried as a juvenile and are expected to ask for a change of venue.

Mundy, who will try the case in court, is considered one of the top criminal lawyers in Washington. He successfully defended Melvin Downing, accused of the 1976 Berkley Farms market triple murder, getting a not guilty verdict after a witness wounded in the incident identified Downing as the murderer in court.

Mundy also was a principal defense attorney for Sterling Tucker when the City Council chariman faced possible expulsion from office for allegedly violating a city charter prohibition on outside employment by the council chairman.

"I think it would be very hard for people who have read about everything that's supposedly gone on in this case to serve on an impartial jury," Garvin said. "It's just impossible at this point."

Garvin said the members of her group have met with numerous people within the county, including church and civic groups, and political action committees, to ask for contributions.

"Our largest pledge thus far is $500 from a church group," she said."I think there is widespread feeling that this case is going to be important to police-community relations in the future and it's important that exactly what happened come out at the trial."

The defense fund group is planning several fund-raisers, is selling "Free Terrance Johnson" T-shirts and, until recently, was running a strongly worded fund appeal on a local radio station particularily popular among blacks.

Johnson, who was charged as an adult, has remained jailed in the county detention center in Upper Marlboro since the morning of the shootings.

District Court Judge Louis DiTrani, calling the shootings "so shocking that they have left the community in a state of disbelief," set bond at $1,050,000 for Johnson. This is believed to be one of the highest bonds ever set in Maryland for a juvenile.

"Terrance is holding up fairly well," said Garvin, who had visited him. "He has enrolled in Bible classes at the prison and is keeping himself as active as possible.