TUCSON, Arizona – A contractor in southern Arizona pleaded guilty to knowingly hiring illegal immigrants, the first case in that state in which federal authorities filed criminal charges instead of imposing a fine.

Ivan Hardt, president of Sun Dry Wall & Stucco Inc., based in the city of Sierra Vista, pleaded guilty Friday to the misdemeanor charge and could face up to six months in prison when he is sentenced on Jan. 26.

Local media said Hardt also pleaded guilty to a felony charge of conspiring to harbor illegal immigrants, although his attorney said that charge will be dropped if he agrees to pay a $450,000 fine.

The lawyer said his client plans to pay the full amount, according to the reports.

In March 2007, immigration agents raided the company’s facilities and discovered that some of the employees were using forged immigration documents.

The federal government said the case was the fruit of a new federal policy toward violators of immigration laws. Whereas companies used to face only fines for hiring illegal immigrants, they now run the risk of criminal charges.

Jose A. Gutierrez Tapia, the foreman in charge of stucco crews for the company, pleaded guilty to knowingly hiring at least 10 undocumented immigrants and was sentenced to two months in prison and three years of supervised release.