Antonieta Bonifacio Aguon, 44, was charged with preparing about 275 fraudulent U.S. income tax returns for Northern Mariana residents in order to claim the Earned Income Tax Credit, a refund for low-income working individuals and families.

"We are proud to bring the first tax prosecution in the CNMI," said Leonardo Rapadas, U.S. Attorney for the Commonwealth of the Northern Mariana Islands and Guam. "We will not permit criminals to use ... residents in tax fraud schemes."

Between March 2006 and April 2007, the false returns cost the United States about $850,000.

Most residents of the U.S. territory are not required to file returns with the U.S. IRS, and they aren't eligible for the Earned Income Tax Credit. Instead, they pay their taxes to the territorial government.

Aguon was accused of using recruiters to bring her taxpayer information, enabling her to file the false tax returns, according to the U.S. Attorney's Office. Both Aguon and the recruiters charged a 5 percent fee of the tax refund.

Northern Mariana taxpayers who received improper refunds should file amended U.S. tax returns to repay the money, according to the IRS.

The Earned Income Tax Credit is worth up to $4,536 for qualified filers of 2006 returns with a family of two or more children. It refunds payroll and income taxes to low-income people. Qualified taxpayers get a refund when the credit exceeds the amount of taxes owed, and those who do not owe taxes also qualify but must file a return.