Vehicles can be searched without a warrant if police have probable cause to believe the vehicle contains evidence of a crime. Read on to find out how this critical law can make a difference in your criminal case.The Fourth Amendment's rule against unreasonable search and seizures means that police may not search you or your property unless one of the following is true:. Searches Without a Warrant. Law enforcement officials must obtain a valid warrant to conduct a search of an individual's property, with certain exceptions. According to the fourth amendment, the warrant requirement is that there must be probable cause before it can be issued. The Fourth Amendment protects you from unreasonable searches and seizures. The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated. If the police searched your house without leaving a copy of the search warrant, it raises concerns about a potential violation of your Fourth Amendment rights. What Does the Fourth Amendment Mean?