In the event a witness served with a subpoena by the Attorney General under this chapter fails or refuses to obey same or produce documentary material as provided herein, or to give testimony, relevant or material, to the investigation being conducted, the Attorney General may petition the District Court for an order requiring said witness to attend and testify or produce the documentary material demanded; thereafter, any failure or refusal on the part of the witness to obey such order of court may be punishable by the court as a contempt thereof.