225 ILCS 335/9.4
The Department has power to subpoena and bring before it any person in this State and to take the oral or written testimony , or to compel the production of any books, papers, records, documents, exhibits, or other materials that the Secretary or his or her designee deems relevant or material to an investigation or hearing conducted by the Department, with the same fees and mileage and in the same manner as prescribed by law in judicial proceedings in civil cases in courts of this State.
The Secretary, the designated hearing officer, any member of the Board, or a certified shorthand court reporter may administer oaths to witnesses at any hearing that the Department conducts . Notwithstanding any other statute or Department rule to the contrary, all requests for testimony or production of documents or records shall be in accordance with this Act.
225 ILCS 335/9.4