Search and seizure
||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (December 2010)|
Search and seizure is a procedure used in many civil law and common law legal systems whereby police or other authorities and their agents, who suspect that a crime has been committed, do a search of a person's property and confiscate any relevant evidence to the crime.
Some countries have provisions in their constitutions that provide the public with the right to be free from "unreasonable" search and seizure. This right is generally based on the premise that everyone is entitled to a reasonable right to privacy.
Though interpretation may vary, this right sometimes requires law enforcement to obtain a search warrant before engaging in any form of search and seizure. In cases where evidence is seized in a search, that evidence might be rejected by court procedures, such as with a motion to suppress the evidence under the exclusionary rule.
United States 
The Fourth Amendment to the United States Constitution provides that:
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
The text of the amendment is brief, and most of the law determining what constitutes an unlawful search and seizure is found in court rulings. The brief definitions of the terms "search" and "seizure" was concisely summarized in United States v. Jacobsen, which said that the Fourth Amendment:
"protects two types of expectations, one involving 'searches', the other 'seizures'. A search occurs when an expectation of privacy that society is prepared to consider reasonable is infringed. A seizure of property occurs where there is some meaningful interference with an individual's possessory interests in that property."
The general rule under the Constitution is that a valid warrant is required for a valid search. There are, however, several exceptions to this rule, based on the language of the fourth amendment that "the people" are to be "secure ... against unreasonable searches and seizures".
For instance, the owner of the property in question may consent to the search. The consent must be voluntary, but there is no clear test to determine whether or not it is; rather, a court will consider the "totality of the circumstances" in assessing whether consent was voluntary. Police officers are not required to advise a suspect that he may refuse. There are also some circumstances in which a third party who has equal control, i.e. common authority, over the property may consent to a search.
When an individual does not possess a "reasonable expectation of privacy" that society is willing to acknowledge in a particular piece of property, any interference by the government with regard to that property is not considered a search for Fourth Amendment purposes, and a warrant is never required. For example, courts have found that a person does not possess a reasonable expectation of privacy in information transferred to a third party, such as writing on the outside of an envelope sent through the mail or left for pick-up in an area where others might view it. While that does not mean that the person has no reasonable expectation of privacy in the contents of that envelope, the Court has held that one does not possess a reasonable expectation of privacy that society is willing to acknowledge in the contents of garbage left outside the curtilage of a home.
There is also a lowered expectation of privacy inside of motor vehicles. This "automobile exception" has been summarized by St. Mary's University law scholar Professor Gerald Reamey in "Reamey's Rule" as "never, ever, ever put anything in your vehicle that you do not want the police to see". Nevertheless, a 'bright line' has been drawn at the doorstep of person's homes, however, so that whenever the government intrudes inside, their action is considered a search for Fourth Amendment purpose and must always be accompanied by a search warrant (absent exigent circumstances).
Courts have also established an "exigent circumstances" exception to the warrant requirement. "Exigent circumstances" simply means that the officers must act quickly. Typically, this is because police have a reasonable belief that evidence is in imminent danger of being removed or destroyed, but there is still a probable cause requirement. Exigent circumstances may also exist where there is a continuing danger, or where officers have a reasonable belief that people in need of assistance are present. This includes when the police are in 'hot pursuit of a fleeing felon.' In this circumstance, so long as there is probable cause, police may follow the suspect into a residence and seize any evidence in plain view.
Certain limited searches are also allowed during an investigatory stop or incident to an arrest. These searches are called refined searches.
While the interpretations of the U.S. Supreme Court are binding on all federal courts interpreting the U.S. Constitution, there is some variance in the specifics from state to state, for two reasons. First, if an issue has not been decided by the U.S. Supreme Court, then a lower court makes a ruling of "first impression" on the issue, and sometimes two different lower courts will reach different interpretations. Second, virtually all state constitutions also contain provisions regarding search and seizure. Those provisions cannot reduce the protections offered by the U.S. Constitution, but they can provide additional protections such that a search deemed "reasonable" under the U.S. Constitution might nonetheless be unreasonable under the law of a particular state.
The primary remedy in illegal search cases is known as the "exclusionary rule". This means that any evidence obtained through an illegal search is excluded and cannot be used against the defendant at his or her trial. There are some narrow exceptions to this rule. For instance, if police officers acted in good faith—perhaps pursuant to a warrant that turned out to be invalid, but that the officers had believed valid at the time of the search—evidence may be admitted.
Figurative or constructive searches 
In corporate and administrative law there has been an evolution of Supreme Court interpretation in favor of stronger government in regards to investigatory power. In Federal Trade Commission v. American Tobacco Co., the Supreme Court ruled that the FTC, while having been granted a broad subpoena power, did not have the right to a general "fishing expedition" into the private papers, to search both relevant and irrelevant, hoping that something would come up. Justice Holmes ruled that this would go against "the spirit and the letter" of the Fourth Amendment.
In the 1946 case of Oklahoma Press Pub. Co. v. Walling, there was a distinction made between a "figurative or constructive search" and an actual search and seizure. The court held that constructive searches are limited by the Fourth Amendment, where actual search and seizure requires a warrant based on “probable cause”. In the case of a constructive search where the records and papers sought are of corporate character, the court held that the Fourth Amendment does not apply, since corporations are not entitled to all the constitutional protections created in order to protect the rights of private individuals.
See also 
- Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)
- No-knock warrant
- Immigration and Customs Enforcement (ICE)
- United States Border Patrol
- United States Customs and Border Protection (CBP)
- United States Marshals Service
- United States Secret Service
- Minimally intrusive warrantless search
- Search and Seizure Law in Pennsylvania
- "U.S. Const. amend. IV". Official Bill of Rights in the National Archives. U.S. National Archives. Retrieved 23 November 2012.
- United States v. Jacobsen, 466 U.S. 109, 113 (1984)
- Barry, Donald D., and Howard R. Whitcomb, The legal foundations of public administration (Lanham, Md: Rowman & Littlefield Publishers), 122.
- Federal Trade Commission v. American Tobacco Co., 264 U.S. 298 (1924)
- Oklahoma Press Pub. Co. v. Walling, 327 U.S. 186 (1946)