The Fourth Amendment requires the government to obtain a warrant based on probable cause to conduct a legal search and seizure. When probable cause crops up during legal situations, it is referring to a reasonable conviction that someone has or intends to commit a crime.The Fourth Amendment permits the officer to search the vehicle's interior so long as they have probable cause. There was no showing or declaration of probable cause. Writs of Assistance. Automobile Exception. Probable cause is present when the police officer has a reasonable belief in the guilt of the suspect based on the facts and information prior to the arrest. One of the best ways to protect your rights is to know your rights. An illegal search and seizure is one that is performed without a proper warrant or probable cause. Generally, the police cannot simply search a vehicle.