Alvin C. Frost, the embattled D.C. government financial analyst who alleged wrongdoing by his bosses, held a news conference at a downtown restaurant yesterday to announce he will resign -- but then learned the city had already placed him on leave and was considering firing him.

Frost, 38, has been accused by his superiors of insubordination because he changed the secret computer password to a D.C. treasurer's office account, refused to tell his bosses the new password, and then said he had forgotten it.

But yesterday Frost announced he would conduct a guess-the-password contest using a newspaper advertisement, and would award 10 winners a tour of Washington and a lunch with him.

City Administrator Thomas Downs said that he issued a letter yesterday placing Frost on leave and informing him of possible further disciplinary action, but Downs said he could not discuss the reason for the personnel action.

At a news conference at the Old Ebbitt Grill, Frost announced he would resign as a $35,167 senior cash management analyst on March 15, but he declined to comment on previous statements that he may run for city office.

Frost also called on Mayor Marion Barry to intervene to stop what Frost said were "economic threats" against his friends, family and co-workers to get them to pressure Frost to stop his criticism of the Barry administration. Frost said those threats were made in several recent anonymous calls to his associates.

"I will refrain from discussions of possible wrongdoing if [Barry] will refrain from efforts of intimidating me, my family, my friends and colleagues," he said.

Downs denied that city officials are aware of any threats, calling Frost's allegation "baseless." He said Frost should alert police.

Frost, a city employe since 1982, has accused top finance officials of mismanagement and incompetence regarding the handling of city investments and has called on Barry to suspend Deputy Mayor Alphonse G. Hill and three of Hill's high ranking deputies. Frost said he had provided documents sought by the FBI and the Internal Revenue Service last October in connection with an investigation of Hill, but he said he had no further knowledge of wrongdoing.

Frost said he would resign partly because he had been transferred last week to a new job without any duties. "I have no job, nothing to do," he said. "I have an office and a desk."

When he learned he had been placed on administrative leave with pay, Frost said, "Oh, good. I get paid leave [and] . . . I can spend two weeks talking to my lawyers" about a possible challenge to city officials.