While the police ordinarily must obtain a warrant to conduct a search of a private area, exigent circumstances sometimes justify a warrantless search. What sort of exigency might allow police officers to search without a warrant?
Exigency searches are limited in scope. For example, if the exigency involves securing a fleeing suspect and there is no evidence he is armed, the police cannot search a bureau’s drawers or other small areas under the exigency exception.
Exigency searches can sometimes justify warrantless searches of individuals and their personal effects. Exigency searches of individuals are less common than exigency searches of buildings because if the police have probable cause to believe a person has been involved in criminal activity, there will usually be an arrest. If the suspect is arrested, the police are entitled to search his body and his belongings incident to that arrest (and the exigency argument is unnecessary).
Police officers also have the right to conduct protective sweeps without a warrant. A protective sweep is similar in some ways to an exigency search. When police officers have made an arrest or are searching for a suspect in a particular (private) location, they are permitted to walk through the location in order to ensure there is nothing present that can harm them. A protective sweep must be limited in scope to areas that could contain a dangerous person or item – it does not permit a full search of everything within the location.
Finally, if the police believe there is evidence inside of a private area, they can secure the premises by creating a physical barrier around the location (either with officers or crime tape) and wait for a warrant. While they are not allowed to search until the warrant has been authorized, the cops are allowed to restrict access to the location while waiting for a judge or magistrate to consider the application for a warrant.