U.S. District Court Judge James C. Cacheris scathingly rebuked a federal prosecutor in open court in Alexandria Monday and then summoned U.S. Attorney Elsie L. Munsell to his chambers for seeking an indictment in a case in which the judge was the alleged victim.

Cacheris, saying that Munsell's office was "out of bounds," said he had advised against the indictment and was incensed that the case was being brought before him.

"Why didn't you ask me before you indicted him? . . . Didn't you think I'm entitled to that courtesy as a U.S. district judge?" Cacheris asked Assistant U.S. attorney Joseph Aronica, Munsell's chief criminal prosecutor in Alexandria.

"Did you want me to execute him and try him in his absence? Did you want me to do that as the victim in his case? I consider this highly incompetent . . . , " said the judge, who is known for his normaLly cool temperament.

Munsell, the chief prosecutor for eastern Virginia, has been under fire in recent months amid rumors that she may not win reappointment this fall. She issued a statement yesterday, saying there was "some misunderstanding" about Cacheris' attitude on the case. She said she had met with the judge "and the matter has been resolved between us . . . .

"This office has apologized to the judge, in open court and privately," she said. "It is my hope that future differences, if any, can be resolved without this unfortunate kind of confrontation."

Aronica also apologized when called before the judge Monday, saying he was unaware that the case, involving a Virginia prisoner who allegedly sent the judge a threatening letter, would come before Cacheris. He also told Cacheris he was unaware the judge had advised against an indictment.

"Apparently you're not running a very good office, are you?" Cacheris shot back. "You're supposed to be running the criminal section and you're not running it as far as I'm concerned . . . . You ought to know what's going on in your office . . . ."

The matter arose when Cacheris recognized the name of Harry M. Mayo on an indictment presented to him by Assistant U.S. Attorney Ken Melson.

Mayo, whom Cacheris had sentenced to 18 years for armed bank robbery in January, was being indicted on a charge of mailing a threat to Cacheris and to a prosecutor in Alexandria.

Mayo, a prisoner at Virginia's Nottaway Correctional Center, sent a letter Jan. 7 to Cacheris "containing threats to injure him and his children," the indictment said.

Cacheris said receiving the indictment put him in "the embarr- assing position now of trying to set bond for him when I'm the victim."

The judge refused to accept the indictment and told Melson that "I want to see Munsell at 9 o'clock tomorrow morning because I am put out over it . . . There are several other matters I want to discuss with her, too. . . . You could've indicted him if you wanted to, but I think you should have let me know . . . . I'm really hot."

Cacheris said he had advised against indicting Mayo because the indictment "would create more problems." Mayo had also sent a letter of apology to Cacheris, according to sources.

The judge told Melson he believed he acted "in good faith." But to Aronica he said: "I'm raising my voice and I'm telling you don't you ever do that again in my courtroom . . . . Don't you ever have the audacity to indict someone and I'm the putative victim without telling me . . . . I've never seen such a disgusting display, such an embarrassing situation."

Mayo was indicted Tuesday on a charge of threatening the prosecutor -- but not Cacheris. That indictment was presented to Judge Albert V. Bryan Jr., who also sits in Alexandria.