A Kent couple were sentenced Thursday in U.S. District Court in Seattle to prison terms for their use of a tax zapper software to hide cash sales and reduce the taxes owed at their chain of Thai restaurants.

Chadillada Lapangkura, 40, was sentenced to six months in prison, and Pornchai Chaiseeha, 42, was sentenced to four months in prison after pleading guilty in August to conspiracy to defraud the government by hiding more than $1 million in income, according to a U.S. Department of Justice news release.

“They came to this country, a land of opportunity… and then didn’t pay their taxes, and got rich,” U.S. District Judge James L. Robart said at the sentencing hearing.

“Use of this tax zapper software not only cheats on state and federal taxes, it gives a business an unfair advantage over competitors who play by the rules,” U.S. Attorney Brian T. Moran said. “These cases are time intensive to investigate, and I commend federal and state investigators for their work. These defendants thought with a computer key stroke they could get away with this fraud. They were wrong.”

According to records filed in the case, Chaiseeha and Lapangkura were part owners of the chain that has Thai restaurants in Washington, Oregon and Hawaii. Some of the restaurants operated under the name Bai Tong, and some were called Noi.

The restaurants used a point-of-sale computer system that included a cash suppression or Zapper software program that modifies the sales records by removing cash sales from the business records, according to the news release. Between 2010 and 2016, the two had the Zapper software operating at their Redmond and Tukwila restaurants and at their Bend, Oregon restaurant.

The restaurants earned $1.03 million in cash income that was never reported on state or federal tax returns, resulting in an agreed tax loss of $299,806. The pair also used the unreported cash to pay employees under the table, avoiding state and federal employment taxes. Finally, some of the cash proceeds were siphoned off to bank accounts in Thailand, and the existence of those accounts was not reported on their income tax returns.

“Ms. Lapangkura and Mr. Chaiseeha’s actions cheated their fellow taxpayers and community members,” said Justin Campbell, IRS-Criminal Investigation special agent in charge. “IRS-Criminal Investigation stands behind the honest business owners and other taxpayers in the community that pay their fair share. Today, Ms. Lapangkura and Mr. Chaiseeha were held accountable for their shameful conduct.”

Lapangkura was ordered to pay a $10,000 fine, and Chaiseeha must pay a $7,500 fine. Both must perform 80 hours of community service during a two-year period of supervised release following their prison terms. Because the couple has young children, the prison terms will be staggered so that one parent remains with the children.

The defendants have paid $299,806 in state and federal taxes as part of the criminal case. The IRS may also assess other taxes, penalties and interest through its civil processes.

The case was investigated by the Internal Revenue Service Criminal Investigation and Homeland Security Investigations, with assistance from the Washington State Department of Revenue.