An Andalusia couple indicted by a federal grand jury in 2010 for allegedly conspiring to defraud the U.S. government, tax evasion and filing a false claim for a tax refund has pleaded guilty.

A statement released Tuesday by the U.S. Justice Department and the Internal Revenue Service (IRS) stated Thomas K. Frye, a pharmacist, and his wife, Kathy M. Frye, plead to the conspiracy charge.

According to court documents, beginning in 1999, the Fryes conspired to defraud the United States by submitting IRS forms to their employers that falsely claimed they were exempt from federal income taxes. When the IRS attempted to collect back taxes owed by the couple, Mr. Frye submitted false financial instruments to the IRS in purported payment of his and his wife’s tax liability.

“In one such instrument, Mr. Frye represented to the IRS that the false instrument had a value of $100 billion,” the statement read.

Court records also established that, as part of the conspiracy, the Fryes filed false federal income tax returns for the years 2000 through 2007 that substantially understated their incomes.

Sentencing has not yet been scheduled. The Fryes face a potential maximum of five years in prison, three years of supervised release, an order of restitution and a maximum fine of $250,000, or twice the loss caused by the offense.