Abbott Laboratories is under investigation by the U.S. Department of Justice, the company confirmed Friday, almost a year after it shut down a Michigan baby-formula plant after illnesses were reported.

Abbott did not specify what aspect of the company is under Justice Department scrutiny.

“DOJ has informed us of its investigation and we’re cooperating fully,” an Abbott spokesperson said in a statement to NBC News.

The Wall Street Journal reported earlier Friday that the Justice Department was investigating conduct at Abbott’s plant in Sturgis, Michigan, citing people familiar with the matter who it did not name. NBC News has not independently confirmed the nature of the investigation. The Department of Justice did not immediately respond to a request for comment from NBC News.

Abbott voluntarily shut down production at its Sturgis infant formula manufacturing plant on Feb. 17, 2022, after infants who consumed formula made at the plant became sick.