The department shall:
   A.   Prevent the commission of crime and breach of the peace, suppress riots and disorderly assemblages, prevent the commission of acts injurious to the quiet and good order of the city or to persons or property whether private or public.
   B.   Enforce the laws under Arizona Revised Statutes, the city charter and this code except where the enforcing authority is delegated to someone else and in such event the department shall cooperate by exercising its arrest authority when requested to do so. (1972 Code)