625 ILCS 45/2-1

Enforcement.) It is the duty of all Conservation Police Officers and other employees of the Department designated by the Director to enforce this Act, and all sheriffs, deputy sheriffs and other police officers to arrest any person detected in violation of any of the provisions of this Act. It is further the duty of all such officers to make prompt investigation of any violation of the provisions of this Act reported by any other person, and to cause a complaint to be filed before the circuit court if there seems just ground for such complaint and evidence procurable to support the same.