An inspector for the Division of Housing Inspection entered an apartment building to make a routine annual inspection for violations of the city housing code. That inspector learned that D was using the rear of his leasehold as a personal residence. The inspector demanded entry, but D refused because the inspector lacked a search warrant. Repeated requests were met with the same response. A complaint was filed for refusing to permit a lawful inspection in violation of city codes. D brought this action in a California Superior Court alleging that he was awaiting trial on a criminal charge of violating the San Francisco Housing Code by refusing to permit a warrantless inspection of his residence, and that a writ of prohibition should issue to the criminal court because the ordinance authorizing such inspections is unconstitutional on its face. The Superior Court denied the writ, the District Court of Appeal affirmed, and the Supreme Court of California denied a petition for hearing. The Supreme Court granted certiorari.