It is the duty of the police department to apprehend and arrest on view or on warrant and bring to justice violators of the ordinances of the city; to suppress all riots, affrays and unlawful assemblies which may come to their knowledge, and generally to keep the peace; to serve warrants, writs, executions and other processes properly directed and delivered to them; to apprehend and arrest persons violating state laws as provided by law, and to turn them over to proper authorities; and in all respects, to perform all duties pertaining to the offices of police officers. (1992 Code § 13-302)