The Fourth Amendment to the United States Constitution is part of the Bill of Rights. It prohibits unreasonable searches and seizures. In addition, it sets requirements for issuing warrants: warrants must be issued by a judge or magistrate, justified by probable cause, supported by oath or affirmation, and must particularly describe the place to be searched and the persons or things to be seized.
In United States criminal law, probable cause is the standard by which police authorities have reason to obtain a warrant for the arrest of a suspected criminal or the issuing of a search warrant. It is also the standard by which grand juries issue criminal indictments. The principle behind the standard is to limit the power of authorities to perform random or abusive searches, and to promote lawful evidence gathering and procedural form during criminal arrest and prosecution. The standard also applies to personal or property searches.
Search and seizure is a procedure used in many civil law and common law legal systems by which police or other authorities and their agents, who, suspecting that a crime has been committed, commence a search of a person's property and confiscate any relevant evidence found in connection to the crime.
Terry v. Ohio, 392 U.S. 1 (1968), was a landmark decision of the Supreme Court of the United States in which the Court ruled that it is not unconstitutional for American police to "stop and frisk" a person they reasonably suspect to be armed and involved in a crime. Specifically, the decision held that it is not a violation of the Fourth Amendment to the U.S. Constitution's prohibition on unreasonable searches and seizures when a police officer stops a suspect on the street and questions him or her even without probable cause to arrest, so long as the police officer has a reasonable suspicion that the person has committed, is committing, or is about to commit a crime. The Court also ruled that the police officer may perform a quick surface search of the person's outer clothing for weapons if they have reasonable suspicion that the person stopped is "armed and presently dangerous". This reasonable suspicion must be based on "specific and articulable facts", and not merely upon an officer's hunch.
A strip search is a practice of searching a person for weapons or other contraband suspected of being hidden on their body or inside their clothing, and not found by performing a frisk search, but by requiring the person to remove some or all clothing. The search may involve an official performing an intimate person search and inspecting their personal effects and body cavities. A strip search is more intrusive than a frisk and requires legal authority. Regulations covering strip searches vary considerably and may be mandatory in some situations or discretionary in others.
A Terry stop in the United States allows the police to briefly detain a person based on reasonable suspicion of involvement in criminal activity. Reasonable suspicion is a lower standard than probable cause which is needed for arrest. When police stop and search a pedestrian, this is commonly known as a stop and frisk. When police stop an automobile, this is known as a traffic stop. If the police stop a motor vehicle on minor infringements in order to investigate other suspected criminal activity, this is known as a pretextual stop. Additional rules apply to stops that occur on a bus.
Reasonable suspicion is a legal standard of proof in United States law that is less than probable cause, the legal standard for arrests and warrants, but more than an "inchoate and unparticularized suspicion or 'hunch'"; it must be based on "specific and articulable facts", "taken together with rational inferences from those facts", and the suspicion must be associated with the specific individual. If police additionally have reasonable suspicion that a person so detained is armed and dangerous, they may "frisk" the person for weapons, but not for contraband like drugs. However, if the police develop probable cause during a weapons frisk, they may then conduct a full search. Reasonable suspicion is evaluated using the "reasonable person" or "reasonable officer" standard, in which said person in the same circumstances could reasonably suspect a person has been, is, or is about to be engaged in criminal activity; it depends upon the totality of circumstances, and can result from a combination of particular facts, even if each is individually innocuous.
In the United States, open carry refers to the practice of visibly carrying a firearm in public places, as distinguished from concealed carry, where firearms cannot be seen by the casual observer. To "carry" in this context indicates that the firearm is kept readily accessible on the person, within a holster or attached to a sling. Carrying a firearm directly in the hands, particularly in a firing position or combat stance, is known as "brandishing" and may constitute a serious crime, but that is not the mode of "carrying" discussed in this article.
Illinois v. Caballes, 543 U.S. 405 (2005), was a United States Supreme Court case in which the Court held that the Fourth Amendment is not violated when the use of a drug-sniffing dog during a routine traffic stop does not unreasonably prolong the length of the stop.
Florida v. Bostick, 501 U.S. 429 (1991), was a United States Supreme Court case that overturned a per se rule imposed by the Florida Supreme Court that held consensual searches of passengers on buses were always unreasonable. The Court ruled that the fact that the search takes place on a bus is one factor in determining whether a suspect feels free to decline the search and walk away from the officers.
Consent searches are searches made by police officers in the United States based on the voluntary consent of the individual whose person or property is being searched. The simplest and most common type of warrantless searches in the United States are searches based upon consent. No warrant, probable cause or reasonable suspicion is required to perform a search if a person, or someone else with the proper authority, consents to a search.
Minnesota v. Dickerson, 508 U.S. 366 (1993), was a decision by the Supreme Court of the United States. The Court unanimously held that, when a police officer who is conducting a lawful patdown search for weapons feels something that plainly is contraband, the object may be seized even though it is not a weapon. By a 6-to-3 vote, however, the court held that the officer in this case had gone beyond the limits of a lawful patdown search before he could determine that the object was contraband, making the search and the subsequent seizure unlawful under the Fourth Amendment.
Whren v. United States, 517 U.S. 806 (1996), was a unanimous United States Supreme Court decision that "declared that any traffic offense committed by a driver was a legitimate legal basis for a stop."
Florida v. Jardines, 569 U.S. 1 (2013), was a United States Supreme Court case which resulted in the decision that police use of a trained detection dog to sniff for narcotics on the front porch of a private home is a "search" within the meaning of the Fourth Amendment to the United States Constitution, and therefore, without consent, requires both probable cause and a search warrant.
United States v. Drayton, 536 U.S. 194 (2002), was a case in which the United States Supreme Court clarified the applicability of Fourth Amendment protections to searches and seizures that occur on buses, as well as the function of consent during searches by law enforcement. During a scheduled stop in Tallahassee, Florida, police officers boarded a Greyhound bus as part of a drug interdiction effort and interviewed passengers. After talking to two of the passengers and asking if they could "check [their] person", officers discovered the two passengers had taped several packages of cocaine to their legs. At trial, the passengers argued that officers violated their Fourth Amendment rights against unreasonable searches and seizures because the police engaged in coercive behavior and never informed them that their participation in the drug interdiction efforts was voluntary.
Navarette v. California, 572 U.S. 393 (2014), was a case in which the United States Supreme Court clarified when police officers may make arrests or conduct temporary detentions based on information provided by anonymous tips. In 2008, police in California received a 911 call that a pickup truck was driving recklessly along a rural highway. Officers spotted a truck matching the description provided in the 911 call and followed the truck for five minutes, but did not observe any suspicious behavior. Nevertheless, officers conducted a traffic stop and discovered 30 pounds (14 kg) of marijuana in the truck. At trial, the occupants of the car argued that the traffic stop violated the Fourth Amendment of the United States Constitution, because the tip was unreliable, and officers did not personally observe criminal activity. Writing for a majority of the Court, Justice Clarence Thomas held that the 911 call was reliable, and that officers need not personally observe criminal activity when acting upon information provided by an anonymous 911 call.
In the law, the totality of the circumstances test refers to a method of analysis where decisions are based on all available information rather than bright-line rules. Under the totality of the circumstances test, courts focus "on all the circumstances of a particular case, rather than any one factor". In the United States, totality tests are used as a method of analysis in several different areas of the law. For example, in United States criminal law, a determination about reasonable suspicion or probable cause is based on a consideration of the totality of the circumstances.
United States v. Sharpe, 470 U.S. 675 (1985), was an important decision of the U.S. Supreme Court in which the Court explained how long police are permitted to stop vehicles as part of an investigatory stop before violating the Fourth Amendment. A seven-member majority of the Court determined the twenty minute stop in this case was legal, so the government won. However, the Court declined to adopt a bright line rule, deciding instead that "common sense and ordinary human experience must govern over rigid criteria." The Court announced that the rule for determining whether a detention is too long will depend on whether the police "diligently pursued" an investigation to quickly confirm or dispel their suspicions. The Court clarified that judges should avoid "unrealistic second-guessing" of police and should take into account "swiftly developing situation[s]." Sharpe has been frequently cited, and is the framework used to challenge unduly prolonged police stops in thousands of criminal cases.
Johnson v. United States, 333 U.S. 10 (1948), was a significant United States Supreme Court decision addressing search warrants and the Fourth Amendment. In this case, where federal agents had probable cause to search a hotel room but did not obtain a warrant, the Court declared the search was "unreasonable."
