The judge evidently thought there could be no obligation on the defendants because there was no tenancy in effect when they succeeded to the ownership. But we do not find liability under the statute so conditioned; on the contrary, that subsection (5) may cover a case where the tenancy has terminated, is emphasized by the treatment, as a proviso, of a situation where the tenancy continues after the succession of ownership. Whether a successor (or a successor to a successor) may be made liable where the thirty days following termination of tenancy may have long antedated the *950succession of ownership, we need not consider; as noted, the present case is central and simpler.