No dog of fierce, dangerous, or vicious propensities and no female dog in heat, whether licensed or not, shall be allowed to run at large or upon the premises of one other than the owner. If any such dog is found running at large in violation of this provision, it shall be taken up and impounded and shall not be released except upon approval of the Chief of Police after payment of the fees provided in § 90.21. However, if any dangerous, fierce, or vicious dog so found at large cannot be safely taken up and impounded, such dog may be slain by any policemen.
(‘82 Code, § 5-604)