While Luigi Mangione today stands trial for the killing of UnitedHealthcare CEO Brian Thompson, the U.S. Justice Department is launching a civil fraud investigation into the conglomerate’s Medicare billing practices.

UnitedHealth, still reeling from the murder of one of its top executives, is reportedly facing a Department of Justice investigation.

UnitedHealth Group shares tumbled early Friday on a report that the U.S. Department of Justice has started an investigation into the health care giant’s Medicare billing practices