California Code, Harbors and Navigation Code - HNC § 663.6

Every vessel subject to this chapter, if under way and lawfully ordered to stop and lie to by a peace officer or harbor policeman authorized to enforce the provisions of this chapter who is either in a uniform of a law enforcement agency or the harbor police or in a vessel that is distinctly marked as belonging to a law enforcement agency or to the harbor police, shall stop immediately and lie to, or shall maneuver in such a way as to permit the peace officer or harbor police vessel to come alongside.