Yesterday afternoon, in the back of a small carry-out restaurant on Central Avenue, the Prince George's County chapter of the NAACP released the "findings" of its three-week investigation into last month's police shooting of suspected shoplifter William Ray.

"We have concluded," said Arthur Jackson, chairman of the chapter's youth division, "that this was a clear case of murder."

To back up this conclusion, Jackson offered the following evidence unearthed by his investigation: four newspaper clippings and a piece of blood-stained cloth that Jackson claimed was taken from the scene of Ray's shooting behind a Baptist church in Seat Pleasant.

One week earlier, in the basement hearing room of Seat Pleasant's City Hall, an ad hoc group of businessmen, police officers and clerymen had held a press conference to express an opposing point of view on the same case.

"This conference has been called because a volatile situation is developing in the community," said Dr. Terrence A. McGuire. "Inflammatory statements and overzealous reporting have inflamed tensions in our community."

Dr. McGuire was asked what evidence he had to back up this conclusion. "You're throwing all these damn questions at me that don't mean a damn thing, he responded, his face reddening with anger. "If you want a response, baby you've got it."

Although the purposes and conclusions of the two conferences were poles apart, the message drawn from each was the same:

When Peter F. Morgan, a white county policeman, shot William Ray, a fleeing, black shoplifting suspect, on Christmas Eve, old and deep emotions were stirred within the inner-Beltway communities of Prince George's.

The issue of police and community relations, of black and white antagonism had not gone away. Although the number of complaints against police for excessive force has dropped substantially, the death of Ray easily revived suspicions.

"Rumors are spreading like fire, from house to house, from street to street," said Henry Arrington, the black mayor of Seat Pleasant. "It's all been what Mrs. So-and-So said or what so-and-so saw. I will attempt not to judge, try or convict anyone and I urge everyone else to refrain from rumor-spreading."

On Wednesday, a Prince George's County grand jury will be presented the evidence amassed in this case. The county State's Attorney Arthur A. Marshall Jr. will present his findings so the jury may decide if the police officer should be indicted.

Morgan's attorney, Samuel Serio, said he will probably encourage his client to testify on his own behalf rather than take the Fifth Amendment.

"That way," Serio said, "if there's an indictment forthcoming, it's against one officer, it's not an indictment of the entire police force."

A separate investigation has been completed by the police department's internal affairs division and is in the hands of Chief John W. Rhoads. He will decide whether to send the internal case to a Police Trial Board, which could remove the temporarily suspended Morgan from the police force.

Nathaniel K. Smith, chairman of the state NAACP youth conference, said the disposition of the Morgan case was not as important as an indictment against the entire Prince George's police force.

"Although there apparently has been a decrease of brutality by police officers in Prince George's, the county government and the police department still do not have things under control," said Smith.

On the other side, Dr. McGuire said the issue was not police brutality, but drugs (the Ray autopsy found that he was a heroin addict).

"Today, we have an extremely serious problem in our community," said McGuire. "That problem, ladies and gentlemen, is dope. I repeat -- dope! I am speaking about smoking dope, shooting dope and dealing dope."

Jack Kornett, leader of the Prince George's Fraternal Order of Police, blamed the press: "There's a historical tendency on the part of the press to pick on Prince George's police," said Cornett. "That's unfortunate because it's a hangover from another era, the tendency is based on incidents that took place in the 1960s."