It shall be the duty of the Animal Control Officer to investigate complaints concerning any dogs which are alleged to be in violation of this Article and to apprehend any dog found by him to be in violation of one or more of the provisions of this Article regarding public nuisances. It shall further be the duty of the Animal Control Officer to apprehend any dog found by him to be in violation of the definition of "public nuisance" in § 81-2, even though no official complaint has been made by a citizen. All such dogs apprehended by the Animal Control Officer or by the Police Department shall be impounded in a suitable place.