Terrence G. Johnson, the Prince George's County youth convicted of slaying a county police officer in 1978, yesterday lost another appeal of his conviction, this one based on a conversation between the presiding judge and a juror in the case.

County Circuit Court Judge Robert Chasanow rejected the argument of Johnson's lawyers that their client was denied his constitutional right to be present during all phases of the 1979 trial when the presiding judge met with a juror to discuss her complaint about the jury foreman. Juror Jacqueline Ball told presiding judge Jacob Levin during that meeting that she felt the foreman was prejudiced, according to Johnson's lawyers.

The lawyers, R. Kenneth Mundy and Allen Lenchek, argued to Chasanow that Levin committed an error grave enough to warrant a new trial by holding the private conversation with Ball and not telling the attorneys or Johnson afterward about the substance of the conversation. Ball had told Levin that she believed the jury foreman was prejudiced because he had told her he felt the black jurors were sticking together.

Race had become a dominant element in the case because of a history of tension between the county's black community and its mostly white police force. Johnson is black and the two officers shot to death by Johnson were white. Johnson, serving a 25-year prison term, was convicted of manslaughter in the death of one officer and acquitted by reason of insanity in the other.

Chasanow ruled that the remark by the jury foreman was "relatively innocuous" and there was no evidence of bias on his part. Therefore, Chasanow, concluded, Judge Levin's meeting with Ball did not prejudice Johnson's case.

Johnson's attorneys have exhausted appeals through the state courts and the U.S. Supreme Court, but because they learned of the conversation after these appeals were filed, they may go through the appeals process again, Lenchek said.