What is the Fourth Amendment?
The Fourth Amendment of the United States Constitution protects citizens from unreasonable searches and seizures by law enforcement officers. A search and seizure is considered unreasonable if it is conducted by police without a valid search warrant, and does not fall under an exception to the warrant requirement.

What is a search warrant?
A judge issues a search warrant to authorize law enforcement officers to search a particular location and seize specific items. To obtain a search warrant, police must show probable cause that a crime was committed and that items connected to the crime are likely to be found in the place specified by the warrant.

What constitutes a valid search warrant?
A valid search warrant must meet four requirements: (1) the warrant must be filed in good faith by a law enforcement officer; (2) the warrant must be based on reliable information showing probable cause to search; (3) the warrant must be issued by a neutral and detached magistrate; and (4) the warrant must state specifically the place to be searched and the items to be seized.

Where can police search and what can they seize under a warrant?
Police may only search the particular area and seize the specific items called for in the search warrant. Police may search outside the scope of the warrant only if they are protecting their safety or the safety of others, or if they are acting to prevent the destruction of evidence. Police may seize objects not specified in the warrant only if they are in plain view during the course of the search.

Can police conduct a search without a search warrant?
Yes. Under some circumstances, police are authorized to conduct a search without first obtaining a search warrant. Common exceptions to the warrant requirement include:

Consent. Police may conduct a search without a search warrant if they obtain consent. Consent must be freely and voluntarily given by a person with a reasonable expectation of privacy in the area or property to be searched.
Plain View. An officer may seize evidence without a warrant if an officer is on the premises lawfully and the evidence is found in plain view.
Search incident to arrest. While conducting a lawful arrest, an officer may search an individual’s person and their immediate surroundings for weapons or other items that may harm the officer. If a person is arrested in or near a vehicle, the officer has the right to search the passenger compartment of that vehicle.
Exigent Circumstances. Police are not required to obtain a search warrant if they reasonably believe that evidence may be destroyed or others may be placed in danger in the time it would take to secure the warrant.
Automobile Exception. An officer may search a vehicle if they have a reasonable belief that contraband is contained inside the vehicle.
Hot Pursuit. Police may enter a private dwelling if they are in “hot pursuit” of a fleeing criminal. Once inside a dwelling, police may search the entire area without first obtaining a search warrant.
Is it lawful for an officer to pat me down without a warrant?
A police officer may stop an individual to conduct a field interview if the officer has reasonable suspicion that criminal activity has been, is being or is about to be committed. During the field interview, the officer may conduct a pat-down search of the outer garments for weapons if the officer has a reasonable fear for his or her own safety as well as that of others.

What recourse do I have if a search was conducted unlawfully?
If evidence is obtained without a valid search warrant, and no exception to the warrant requirement applies, the evidence may be subject to the exclusionary rule. The exclusionary rule prevents illegally obtained evidence from being admitted in a court of law. Evidence gathered on the basis of illegally obtained evidence (known as “fruit of the poisonous tree”) will also be excluded.