Edward Thomas Mann, accused of killing three persons and assaulting 23 at the IBM Corporation's Bethesda headquarters last May, suffers from paranoia, yet is still mentally competent to stand trial, two psychiatrists testified yesterday for the prosecution.

The testimony of those psychiatrists ran counter to opinions expressed earlier by four psychiatrists who testified for the defense that Mann's paranoia is so "global" in nature that it leaves him incapable of making rational decisions about his defense.

The hearings this week, held by Judge William C. Miller, will determine whether Mann is rational enough to assist in his defense and competent to stand trial.

If found mentally competent, Mann could be sentenced to death if the guilty plea he has offered is accepted. If he is found unable to assist in his defense, he would be sent to a state mental hospital.

Questioning one of the psychiatrists who had testified for the prosecution, Miller concentrated yesterday on whether Mann's guilty plea represented an attempt to commit "judicial suicide."

Psychiatrist Jack Clermont, clinical director at the Clifton T. Perkins state hospital where Mann was moved last week after an apparent suicide attempt, had testified that Mann's paranoia is of a moderate nature and applies to a limited number of circumstances.

On a severity scale of one to ten, with one being the most moderate, Clermont said he would rate Mann at four.

Mann's attorneys, defending him against his wishes, contend that his mental illness, manifested in a belief that there is a "global" conspiracy against him, is so all-encompassing that it includes the court system.

Mann has objected to the mental competence hearings and said that he wants to die. Clermont said he believed Mann wants to die because he is "tired of waiting around" and that Mann also wants to use the court system to show he is the victim of an attempt by IBM, where he was once employed, to destroy him.

"Does that suggest logical thinking to you?" Miller asked Clermont.

The psychiatrist replied that it would be speculation to interpret Mann's views about IBM as indicating that Mann feels the court is part of a conspiracy or that he is incompetent to stand trial.

Pressed by the judge on why Mann changed his plea to guilty, Clermont said, "Maybe he just wants to be punished."

The judge responded that Mann has "never said he feels guilty about this terrible thing he's done . . . . I think that is more speculation" than saying that Mann might believe the court is part of a conspiracy.

Miller recessed the case until Feb. 7, when two more days of hearings are scheduled.