615 ILCS 5/25

The Attorney General, any State's Attorney of any county or any attorney authorized by the Department of Natural Resources shall have the power to represent said Department, and in the name of the State of Illinois, invoke for the purposes specified in this act, all of the power of the State to prevent the wrongs and injuries herein referred to, and for that purpose, such Attorney General, State's attorney or authorized attorney shall be deemed to be the proper representative of the State, with full power and authority upon its behalf to prosecute all necessary suits or actions.