Investigators said Miron had improperly billed school districts for overhead and expenses by applying an additional markup to its labor charges above what it had actually paid workers in wages.

“They intentionally reported inflated wages paid to their employees and what makes this worse it that they were doing it to school districts which we all know are struggling,” says Berceau.

With revenues of $680 million in 2013 and some 1,200 employees at its various offices, including Madison, Miron is one of the largest construction companies in the state. Projects of note include the $143 million expansion of Lambeau Field and new headquarters for Plexus Corp. In 2010, the firm was named the “Most Admired Company in WI” by Corporate Report magazine.

Miron officials did not respond to a request for comment for this report but had issued a statement in April saying the federal investigation centered on just a few of more than 150 Wisconsin public school districts projects it completed between 2003 and 2008. It said its billing practices were “consistent with others in the industry."