65 ILCS 5/10-1-39
Any person who shall be served with a subpoena to appear and testify, or to produce books and papers, issued by the commission or by any commissioner or by any board or person acting under the orders of the commission in the course of an investigation conducted either under the provisions of Section 10-1-18 or 10-1-20, and who shall refuse or neglect to appear or to testify, or to produce books and papers relevant to the investigation, as commanded in such subpoena, is guilty of a misdemeanor, and shall, on conviction, be punished as provided in Section 10-1-40. The fees of witnesses for attendance and travel shall be the same as the fees of witnesses before the circuit courts of this state and shall be paid from the appropriation for the expenses of the commission. Any circuit court of this state upon application of any such commissioner, or officer or board, may in his discretion compel the attendance of witnesses, the production of books and papers, and giving of testimony before the commission, or before any such commissioner, investigating board or officer, by attachment for contempt or otherwise in the same manner as the production of evidence may be compelled before such court. Every person who, having taken an oath or made affirmation before a commissioner or officer appointed by the commission authorized to administer oaths shall swear or affirm wilfully, corruptly and falsely shall be guilty of perjury and upon conviction shall be punished accordingly.
65 ILCS 5/10-1-39