When law enforcement is issued a legal search warrant, the warrant has limitations. A search warrant grants permission to law enforcement to conduct a physical search of a specific location to look for certain items. The police officers may not search outside the parameters that are specified in the search warrant. When law enforcement applies for a search warrant, they must demonstrate probable cause based on viable information they have received. All search warrants must be signed by a judge. If law enforcement officers were to conduct a search without a legal search warrant, then the search itself -- and anything law enforcement officers obtained during the search -- is presumed to be unreasonable.