A federal judge in Los Angeles, citing misconduct by a federal prosecutor before a grand jury, yesterday dismissed a 13-count indictment charging Sears, Roebuck and Co. with concealing from U.S. Customs officials $1.1 million in rebates from Japanese television set manufacturers.

U.S. District Judge Manuel Real said special assistant U.S. Attorney Paul Gorman "misused" the grand jury process by calling a grand jury witness who had interests adverse to Sears' and whose testimony was irrelevant. Gorman also had not interviewed the witness in question, Zenith Corp. Chairman John Nevin, before eliciting his grand jury testimony, Real said.

In addition, Gorman made improper remarks before the grand jury concerning import competition between the United States and Japan in the television set market, Real said.

"I think in review of all the material which has been presented to the court, that blind zeal in the prosecution of any criminal defendent, no matter how well intentioned by the prosecutor and no matter what the personal opinion of the prosecutor of the heinous nature of the conduct being investigated, can not justify unfairness in the using of what was designed to be and is an independent arbiter between a citizen and his or her government," Real said from the bench.

"I think unfairness cannot be tolerated," Real continued. "We are dedicated to the dispensation of justice, and I will not be a part of the totality of the grand jury proceedings here that I can only characterize as unfair."

The Justice Department is "looking at a number of options" concerning the case, a spokesman said. The Justice Department could appeal the dismissal, take the case before another grand jury or file a criminal information against the retailer, the spokesman said. An information is a charge made without a grand jury finding.

The Justice Department is also reviewing the transcript of the case before it decides what to do with Gorman, a special prosecutor from Toledo who is supposed to be an expert in customs cases, the spokesman said.

"Judge Real's ruling is most gratifying," said Sears Chairman Edward R. Telling. "The irresponsible and irrational conduct of a few individuals in the Department of Justice who sought to smear Sears' record was an outrage. It is most heartening to find that this is still a nation of laws."

Stephen D. Miller, an attorney representing Sears in Los Angeles, said if the case had gone to trial he would have been prepared to present testimony from the former chief of customs and the former district director of customs for Los Angeles saying that Sears' practices were lawful.