When the chief of police determines that a tow truck service that has been approved to be on the city rotation list commits an unlawful act, or determines that immoral, unethical or other outrageous acts or practices have been committed by a tow truck service, its agents, officers or employees, such acts or practices shall be sufficient grounds for removal from such city rotation tow list. (Ord. 531 § 2 (part), 1990).