815 ILCS 370/9
The Director may file a complaint and apply for, and the circuit court may grant, a temporary restraining order or preliminary or permanent injunction restraining any person from violating or continuing to violate any of the provisions of this Act or any rules and regulations promulgated under this Act notwithstanding the existence of other judicial remedies. Any such injunction may be entered without notice.
The Department, over the signature of the Director, is authorized to issue subpoenas and to bring before the Department any person or persons in this State and to take testimony either orally or by deposition or by exhibit with the same fees and mileage and in the same manner as prescribed by law in judicial proceedings and civil cases in the circuit courts of this State. The Director is authorized to issue subpoenas duces tecum on any or all individuals and records relating to the sale of petroleum or motor fuel. The Director may administer oaths to witnesses at any hearing which the Department is authorized by law to conduct.
815 ILCS 370/9