The filing alleges nearly all 47 returns prepared by Sandoval and his associates that were reviewed by the Internal Revenue Service were subject to false claims that could cost the United States as much $1 million in lost tax revenue.

In Delaware, the department took similar action to bar Carmen J. Martinez and her business, CJM Bookkeeping and Taxes, from preparing federal tax returns for others. Location in Wilmington, Del., Martinez and her business were reported to have prepared more than 7,800 returns since 2010.

Martinez is accused of costing the country as much as $25 million in lost tax revenue between 2010 and 2013 as her customers improperly received average refunds of $5,000 each year. The preparer allegedly claimed false deducts, including unqualified dependents, for clients and also improperly claiming the Child Tax Credit, the Additional Child Tax Credit and tax rate benefits derived from improper filing status as Head of Household or Married Filing Jointly.

Barbara L. Garrett, a Chicago tax return preparer, who worked at several locations, including Instant Tax Service, Preferred Financial and Income Tax Solutions, allegedly claimed deductions from fake businesses. That included allegedly preparing two tax returns for a Chicago Transit Authority bus driver that reported more than $25,000 in combined losses from a transportation company Garrett said her customer owned. In fact, the client did not own such a business.

Among other alleged abuses, Garrett reportedly claimed more $13,000 in fictitious medical expenses and over $2,200 in bogus property tax deductions on a return that also had fake childcare expenses.