The Internal Revenue Service was demanding $90,251 in payments from advocate of the homeless Mitch Snyder at the time of his death, a challenge that Snyder planned to turn into yet another public tirade about national priorities, his longtime companion, Carol Fennelly, said yesterday.

Snyder received a preliminary notice dated June 17 from the IRS, asking for about $50,000 in back taxes and $40,000 in fines to cover $150,000 he received in 1985 and 1986 from the producers of the television movie, "Samaritan," who purchased the rights to his story.

Attorney Jerry Kafka, who was handling the case for Snyder, confirmed the contents of the letter yesterday. IRS officials would not comment.

Fennelly said the IRS inquiry of Snyder came after she provided financial documents relating to the management of the Community for Creative Non-Violence shelter, as part of a separate investigation last winter.

Snyder had maintained that he contributed all his earnings to CCNV, which operated on a $570,000 budget last year. Fennelly said Snyder "relished the thought" of going to trial against the IRS.

"He loved it," she said about the IRS investigation in a lengthy interview. "He was waiting, for years, for them to come after us. He wanted a forum to discuss the priorities of the government and our tax system.

"He was so aware of the possibility {of a trial}, so conscious of it, that the only people we allowed to sign checks here were people we thought would make good defendants in a trial."

Snyder, she said, never signed checks because he did not want "to be involved with accounting and he never wanted to be accused of skimming or anything that could bring him down."

Kafka said he considered the IRS inquiry of Snyder a "run-of-the-mill audit."

"Whether it goes on from here," Kafka said, referring to Snyder's death, "is up to the IRS. I understood he left no estate. In that case, I would expect the service to act reasonably."

Snyder, 46, hanged himself last week in his bedroom in the CCNV shelter at Second and D streets NW. He left behind a note in which he lamented a failed relationship with Fennelly, his companion of more than a dozen years. He was cremated Tuesday and his remains, placed in an oaken urn, were returned to the shelter.

Yesterday, Fennelly relaxed after a tense period of making funeral plans to discuss the future for herself and CCNV. She declined to discuss what single event, if any, she believed led Snyder to despair.

She said their wedding plans had been delayed so they could devote their time to campaigning for the preservation of Initiative 17, the city law that guaranteed the right of shelter to homeless people who request it. She would not characterize the marriage plans as having been "called off."

"It was more important for us to make Initiative 17 happen than for the wedding to happen. And we had 13 years of history to deal with and had to struggle with that. We just needed more time."

Fennelly said she planned to devote the next month to fighting the recent D.C. Council action that effectively gutted Initiative 17, which Snyder persuaded voters to pass in 1984. She will also be sorting through legal suits that Snyder had helped sponsor in the past few years.

Even as she outlined her plans, Fennelly appeared to gear up for battle. She criticized Snyder's detractors, most notably D.C. Council member Nadine P. Winter (D-Ward 6). Within days after Snyder's death, Winter sponsored a bill to name the shelter for him. Fennelly characterized Winter's response as "political."

"She disgusts me . . . she's taking advantage of Mitch's death and it nauseates me. She hurt Mitch. She told lies about him . . . . I find her despicable and find the whole bill despicable," Fennelly said.

Winter's aide, David Watson, declined to comment.

Fennelly said that while she would help to lead CCNV's effort this time, she did not plan to become the permanent replacement for Snyder and act as CCNV spokeswoman.

"I don't want that role," she said. "I think that kind of position is unhealthy for whoever holds it . . . . You begin to believe your own press. Your ego begins to get affected in unhealthy ways . . . .

"Fame and face recognition is a horrible thing. I pray that someone emerges from the group. No one will be able to fill Mitch's shoes. He was the master of the 60-second sound bite . . . but I believe God will provide."