70 ILCS 3715/15
To police such area and to exercise police power with respect thereto and to employ and commission policemen. Such policemen and trustees of the authority are authorized to enforce all ordinances of the authority, to act as conservators of the peace and to arrest, with or without process, any person who breaks the peace or is found violating any ordinance of the authority or any criminal law of this State; and to commit arrested persons for examination without unnecessary delay. All warrants for the violation of ordinances of the authority, or the State criminal law, to whomsoever directed, may be served and executed within the limits of an authority by any policemen thereof. For this purpose policemen have all the common law and statutory power of sheriffs.
70 ILCS 3715/15