A shareholder at one of the companies Sen. Richard Burr sold stock from in the weeks before the coronavirus pandemic rocked the U.S. is suing the senator, alleging the top Republican committed securities fraud by “exploiting material information unavailable to the public.”

The complaint, filed Monday evening in the U.S. District Court for the District of Columbia by attorneys with the litigation boutique Browne George Ross, alleges that Burr “has acted as a scofflaw in a time of national crisis.”