20 ILCS 1705/17
To make such investigations as may be necessary to the performance of its duties. In the course of any such investigation, any qualified person authorized by the Secretary may administer oaths and secure by its subpoena both the attendance and testimony of witnesses and the production of books and papers relevant to such investigation. Any person who is served with a subpoena by the Department to appear and testify or to produce books and papers, in the course of an investigation authorized by law, and who refuses or neglects to appear, or to testify, or to produce books and papers relevant to such investigation, as commanded in such subpoena, commits a Class B misdemeanor. The fees of witnesses for attendance and travel shall be the same as the fees of witnesses before the circuit courts of this State. Any circuit court of this State, upon application of the Department, may compel the attendance of witnesses, the production of books and papers, and giving of testimony before the Department or before any authorized officer or employee thereof, by an attachment for contempt or otherwise, in the same manner as production of evidence may be compelled before such court. Every person who, having taken an oath or made affirmation before the Department or any authorized officer or employee thereof, shall wilfully swear or affirm falsely, shall be guilty of perjury and upon conviction shall be punished accordingly.
20 ILCS 1705/17