Las Vegas ? Anti-tax crusader and author Irwin Schiff was sentenced Friday to more than 13 years in federal prison for advising people that no U.S. law requires them to pay income tax.

Schiff, 78, accused the government of trying to suppress the truth, while his attorney argued he was mentally ill.

Schiff’s earlier boast from the witness stand that he had helped thousands of followers avoid paying $2 billion in taxes was used against him at sentencing.

“Thousands of tax returns, millions and maybe billions of dollars lost,” U.S. Dist. Judge Kent Dawson said as he branded Schiff and his Las Vegas company, Freedom Books, “a flimflam operation” that encouraged others to evade taxes.

“He took their money and left them holding the bag,” the judge said.

The judge also ordered Schiff to pay more than $4.2 million in restitution.