Sec. 3-1-3   Police officers’ duties, generally.
   (a)   The chief of police and the members of the police department shall have the duty of enforcing all the ordinances of the city and the laws of this state within the city, and other duties as may be prescribed by ordinance.
   (b)   It shall be the duty of each member of the police department, upon information furnished him, or upon his knowledge of any violation of the ordinances of the city or of the laws of this state, to secure proper warrants for the arrest and trial of any and all offenders against any ordinances or laws.