The police department of the city shall consist of its chief of police, who shall have supervision over the department, an assistant chief, lieutenant, sergeant, investigator and patrolmen, all appointed by the board of fire and police commissioners, with the exception of the chief of police, who shall be appointed by the mayor with the advice and consent of the city council and with the exception of the investigator who shall be designated from the rank and file by the chief of police, but who shall not have any supervisory authority over other rank and file officers. (Ord. 1178, 9-6-2005)