Whenever there is reasonable cause to believe that a nuisance as defined in this title is kept, maintained or is in existence in any county, the district attorney or the Attorney General, in the name of the people of the State of California, shall, on a proper showing, commence an action in equity to abate and prevent the nuisance and to perpetually enjoin the person conducting or maintaining it, and the owner, lessee or agent of the building, or place, in or upon which the nuisance exists, from maintaining or permitting it. As used herein, a proper showing to commence an action under this title must be based upon evidence independent of the motion picture itself that intentional killing of, or cruelty to, a human being or an animal actually occurred in the production of the motion picture for the purpose of such production.