A federal judge here yesterday barred testimony by an accused highlevel drug operative about murders and shootings allegedly ordered or carried out by the purported ringleader of a $30 million drug smuggling network.

Robert L. Stuckey is a codefendant with alleged drug kingpin Linwood Gray in a five-week-long trail before U.S. District Judge William B. Bryant here. He has told the judge through his attorney that he wants to testify in his own defense that he participated in the drug conspiracy only because he was afraid of Gray.

Bryant ruled, however, that Stuckey's testimony would be prejudicial to Gray and the other eight codefendants because it would present to the jury for the first time allegations that Gray committed or directed numerous violent acts while directing the drug ring.

Instead, he ordered that Stuckey's case be separated immediately from that of the other defendants and tried later.

Prosecutors had argued strenuously that Stuckey should be allowed to testify, because it would give them an opportunity to present evidence to the jury about Gray's allegedly iron-fisted control of the drug ring.

Stuckey's defense would have contrasted sharply with Gray's own testimony Thursday that he was not a drug-mastermind, but merely a exbank robber.

Gary and the other defendants ar facing charges in connection with the alleged drug-running conspiracy through which drugs were shipped fom overseas to D.C.

However, prosecutors have alleged outside the presence of the jury that Gray ordered the murders of at least two of his alleged couriers, the shooting of another, and the ambush of assistant U.S. Attorney Barry Leibowitz outside the federal courthouse here last December.

Although Stuckey's written submission of testimony is under court seal, Leibowitz has said in open court that it deals with "my shooting." Defense attorneys also have commented further that Stuckey intented to accuse Gray of committing or supervising at least three murders and two shootings.

Sources familiar with Stuckey's proposed testimony said it contained specific allegations, for example, that Gray was involved in the murder of missing disc jockey Bob [nighthawk] Terry and helped dispose of the body.

Gray has testifed that Terry is the real drug kingpin, and that he believes Terry is alive and well in the Netherlands. No trace of Terry has been found since he disappeared shortly after he and Gray were involved in a rock concert promotion in the summer of 1977.

Earlier yesterday, alleged Gray lieutenant Carl Cathey Jr. denied any involvement with drugs and supported Gray's testimony that he had stashed $315,000 in bank robbery loot in a Southeast barbershop for 10 years.