(a) Commencement. – Proceedings may be instituted by indictment, by complaint or, when lawful, by information or by arrest or summons without a warrant or complaint.(b) Complaint.- The complaint is a written statement of the essential facts constituting the offense charged. It shall be made upon oath before a committing magistrate or any other person authorized by law to issue a warrant. The complaint may be based upon personal knowledge or upon reasonable information and belief.