A crack house is any building where crack (freebase cocaine) and other illegal narcotics are sold, which has been fortified to delay entry by police officers armed with search warrants. Some strategies used to counter drug trafficking from such houses are the maintenance of high police visibility by placing a number of uniformed patrols in the immediate vicinity of the crack house, the parking of marked patrol cars in front of the crack house, the temporary detention and brief questioning of persons in the vicinity of the crack house reasonably suspected to be engaged in criminal activity, and notification of the property owner that the building is being used for narcotics trafficking and that continued violations may result in action against the property. The Public Works Department enforces all building code violations, and the Fire Marshal's Office enforces all code violations and may order a building closed if the violations are serious. Fire inspectors can conduct safety inspections at any time without prior notice. The Houston Police Department's ability to wipe out crack houses depends on the coordinated efforts of the investigative Operations Command and the Field Operations Command, particularly the tactical units and the Narcotics Division.