A federal judge in the water contamination crisis in Michigan threatened to enter sanctions and a gag order after an engineering company’s public relations firm attempted to influence jurors in a planned trial using deceptive phone calls, personal attacks against lead plaintiffs’ attorney Corey Stern and a billboard truck that circled the courthouse broadcasting obscene messages.

In a Monday order, District Judge Judith Levy of the Eastern District of Michigan gave the engineering firm, Veolia North America, until May 20 to provide more information about the media campaign, organized by its public relations firm, Actum.