It shall be the duty of the Police Department, and each member thereof, to preserve the peace, order, safety and cleanliness of the city and to enforce all provisions of this code, acting under the general supervision of the Mayor; to execute and enforce all orders and directions of the Mayor or Council; to protect citizens in the right, property, safety and lawful enjoyment of life; to enforce and secure public order and welfare; to prevent obstruction to public travel and intercourse and preserve and secure to every person his or her personal liberty and free and lawful association with others.
('74 Code, § 22-19)