225 ILCS 415/23.4
The Department may subpoena and bring before it any person and to take the oral or written testimony or compel the production of any books, papers, records, or any other documents that the Secretary or the Secretary's 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 procedure 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 have power to administer oaths at any hearing which the Department conducts. Notwithstanding any other statute or Department rule to the contrary, all requests for testimony and production of documents or records shall be in accordance with this Act.
225 ILCS 415/23.4