If an officer is lawfully in a location, then items "in plain view" that can be recognized as contraband or the fruits, instrumentalities, or evidence of criminal activity may be lawfully seized as evidence (Warden v. Hayden). A number of subsequent U.S. Supreme Court decisions have further refined and limited this plain-view exception to the search warrant requirement. The Supreme Court's decision in Horton v. California summarized the plain-view doctrine as having two essential components. First, the item must be accessible to an officer's sight, touch, smell, or hearing in the course of other legal actions by the officer. Second, not only must the officer be lawfully in the place where the object is in plain view, but he/she must also have a lawful right of access to the object. The latter requirement means, for example, that although an item deemed by an officer to be evidence of a crime is in plain view through a window, the officer cannot have access to that item except by obtaining a warrant to enter the building in which the item was observed. Further, in Arizona v. Hicks, the Supreme Court held that the crime-related nature of the item must be immediately recognizable without further search or testing. Using a flashlight in darkness to enhance plain view is permitted, however. In addition to visual plain view, the doctrine also encompasses an officer's touch, smell, and hearing. This means that if an officer touches, smells, or hears something that a trained officer logically recognizes as crime-related without further investigation then it is legal to do what is necessary to obtain that item as evidence.