The Perrigo Company, Allegan County’s largest employer, has announced that search warrants were executed at the company’s corporate offices Tuesday evening as part of an investigation by the U.S. Department of Justice Antitrust Division of industry-wide drug pricing in the pharmaceutical industry.

According to USA Today, federal authorities raided the office of Perrigo as a probe into potential price-fixing threatens to ensnare the generic drug maker.

Perrigo, manufacturer of lower-cost in-house brand name drugs, shares were down 4.2% to $73.01 in pre-market trading Wednesday. Perrigo’s U.S. operations are headquartered in Allegan, but its official base was moved to Ireland a couple of years ago for tax purposes.

USA Today said the development offers a window into the Justice Department’s ongoing investigation into alleged collusion among drug companies to set prices artificially high.