The federal government has sued a Las Vegas telemarketing firm it claims has been selling tax scams.
The lawsuit against National Audit Defense Network says the tax schemes have cost the Treasury 324 million dollars during the past three years.
The Justice Department's tax division is seeking an injunction for the company to turn over lists of customers and to bar it from preparing federal income tax returns for others.
The government also seeks to stop the sale of several computer programs, which the feds say advocate improper tax deductions and credits.
National Audit Defense Network touts itself as the nation's largest audit defense firm. A company spokeswoman declined to comment, saying officials had not seen the lawsuit.