65 ILCS 5/1-2-9

Except as provided in Section 1-2-9.1 of this Act, in all actions for the violation of any municipal ordinance, the first process shall be a summons or a warrant. A warrant for the arrest of an accused person may issue upon the affidavit of any person that an ordinance has been violated, and that the person making the complaint has reasonable grounds to believe that the party charged is guilty thereof. Every person arrested upon a warrant, without unnecessary delay, shall be taken before the proper officer for trial.