Three Northern Virginia tax protesters were found guilty yesterday of mail fraud and conspiring to defraud the U.S. government through a marketing scheme they sold to people hoping to avoid federal income taxes.

A U.S. District Court jury in Alexandria, after deliberating all day, returned guilty verdicts against Burton D. Linne and John C. Imlay of Arlington and Jack O. Slater of Annandale, all members of organizations called "Citizens for Dollars" and "American Liberty Information Service," which offered the tax services out of an Arlington apartment.

Linne and Slater also were found guilty of failing to file federal income tax returns.

Sentencing was set for Jan. 31. They each face possible sentences of nearly 100 years in prison.

"If you are going to attempt to assert yourself and confront the authorities and become a dissident," Linne said after his conviction, "you had better be ready for the worst, and today the worst came."

Federal prosecutor Tom Blondin told the jury that Linne and the others had fooled many with their tax schemes. "Linne is a wonderful performer," Blondin said. "He's an impressive speaker . . . . He has ruined a lot of lives."

Taxpayers from several states paid between $2,000 and $32,000 for information they thought would show them how to become a "nontaxpayer" and thus avoid paying federal income tax, according to testimony during the three-day trial.

Prosecutors said the three men sent millions of dollars to the Bahamas for taxpayers seeking to conceal their income from the IRS. The trial did not make clear what happened to the money.

Linne testified that he wired "considerable sums of money out of the country." But he said he stopped in 1984 when he realized he was required to keep records for five years on such transactions. He said he had not kept records because he wanted to protect his customers' privacy.

Linne testified in court that he had not filed an income tax return in 1980 because "I had come to the conclusion I was not a corporate officer . . . . It did not occur to me that as an independent consultant I had a tax obligation. I thought I was a nontaxpayer."

Linne said he later he changed his mind and now believes "there is no such thing as a nontaxpayer as I conceived it . . . . Impeding the IRS is unlawful . . . . If they weren't there we would have to create them," he said.

Imlay, who said the only true money was silver, testified he had been "a courier" for "Citizens for Dollars." Quoting the Bible, he said his views on money "are directly related to my Christian faith." A witness testified that Imlay often pays his restaurant bills with quarters.

Linne's attorney, Stephen R. Pickard, had argued that the defendants were "standing trial for their beliefs in the Constitution."