The FBI says its billboard and social media campaign asking for tips about public corruption in Baltimore aren't related to the federal investigation of Mayor Catherine Pugh.

FBI spokesman Dave Fitz tells The Baltimore Sun that it's just coincidence as federal agents follow the money Pugh earned from her "Healthy Holly" children's books sales.

He says the department pushes the need for tips and information every couple of months, and Pugh isn't the only area person under federal investigation.

Other pending cases involve corruption among officers on the Baltimore Police Gun Trace Task Force, and just this month, authorities announced indictments of nearly 20 people accused in a prison smuggling ring.