The investigation follows the shutdown last year of the Sturgis plant, which worsened a nationwide formula shortage that has continued into a second year.

The DOJ action was first reported by The Wall Street Journal on Friday.

The Consumer Protection Branch has both civil and criminal authority. It was involved last year in a settlement with Abbott that allowed the company to resume operations at its Sturgis plant after Food and Drug Administration inspectors found a potentially deadly bacteria in the facility.

“DOJ has informed us of its investigation and we’re cooperating fully,” Scott Stoffel, a spokesman for Abbott, told The Detroit News.

Abbott’s Sturgis plant is the country’s largest manufacturing plant for infant formula.

The company recalled products including powder formula sold under the labels Similac, Alimentum and EleCare labels after four children became ill with bacterial infections and two died. The company continues to maintain its stance that its products were not related to the infections or deaths.

There are accusations in federal court filings of baby formula being manufactured under conditions that did not meet regulatory standards for quality and safety.

DOJ’s Consumer Protection Branch is also currently pursuing charges against former Blue Blue President Paul Kruse in connection with a 2015 listeria outbreak traced to the company’s ice cream. A hung jury resulted in a mistrial last year, but the criminal case is going to a second jury trial on April 10 in Austin.