615 ILCS 5/26b
The Department of Natural Resources may make such investigations and conduct such hearings as may be necessary to the performance of its duties under this Act. In making any investigation or conducting any hearing the Department may issue subpoenas for the attendance of witnesses, and may administer oaths. Any person who shall be served with a subpoena to appear and testify, or to produce books and papers, and who shall refuse or neglect to appear or to testify, or to produce books and papers relevant to such investigation, as commanded in such subpoena, shall be guilty of a Class B misdemeanor. Any circuit court of this State, upon application of the Department, may compel the attendance of witnesses, the production of books and papers and the giving of testimony before said Department by attachment for contempt as in other cases for refusal to obey the process and order of the court.
615 ILCS 5/26b