The Fourth Amendment to the United States Constitution is part of the Bill of Rights. It prohibits unreasonable searches and seizures and 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. There is no universally accepted definition or formulation for probable cause. One traditional definition, which comes from the U.S. Supreme Court's 1964 decision Beck v. Ohio, is when "whether at [the moment of arrest] the facts and circumstances within [an officer's] knowledge and of which they had reasonably trustworthy information [are] sufficient to warrant a prudent [person] in believing that [a suspect] had committed or was committing an offense."
Mapp v. Ohio, 367 U.S. 643 (1961), was a landmark decision of the U.S. Supreme Court in which the Court ruled that the exclusionary rule, which prevents prosecutors from using evidence in court that was obtained by violating the Fourth Amendment to the U.S. Constitution, applies not only to the federal government but also to the state governments. The Supreme Court accomplished this by use of a principle known as selective incorporation. In Mapp this involved the incorporation of the provisions, as interpreted by the Court, of the Fourth Amendment which is applicable only to actions of the federal government into the Fourteenth Amendment's due process clause which is applicable to actions of the states.
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.
In criminal procedure law of the United States, an exigent circumstance allows law enforcement to enter a structure without a search warrant, or if they have a "knock and announce" warrant, allows them to enter without knocking and waiting for the owner's permission to enter. It must be a situation where people are in imminent danger, evidence faces imminent destruction, or a suspect's escape is imminent. Once entry is obtained, the plain view doctrine applies, allowing the seizure of any evidence or contraband discovered in the course of actions consequent upon the exigent circumstances.
Wolf v. Colorado, 338 U.S. 25 (1949), was a United States Supreme Court case in which the Court held 6—3 that, while the Fourth Amendment was applicable to the states, the exclusionary rule was not a necessary ingredient of the Fourth Amendment's right against warrantless and unreasonable searches and seizures. In Weeks v. United States, 232 U.S. 383 (1914), the Court held that as a matter of judicial implication the exclusionary rule was enforceable in federal courts but not derived from the explicit requirements of the Fourth Amendment. The Wolf Court decided not to incorporate the exclusionary rule as part of the Fourteenth Amendment in large part because the states which had rejected the Weeks Doctrine had not left the right to privacy without other means of protection. However, because most of the states' rules proved to be ineffective in deterrence, the Court overruled Wolf in Mapp v. Ohio, 367 U.S. 643 (1961). That landmark case made history as the exclusionary rule enforceable against the states through the Due Process clause of the Fourteenth Amendment to the same extent that it applied against the federal government.
Weeks v. United States, 232 U.S. 383 (1914) was a United States Supreme Court case in which the Court unanimously held that the warrantless seizure of items from a private residence constitutes a violation of the Fourth Amendment to the U.S. Constitution. It also prevented local officers from securing evidence by means prohibited under the federal exclusionary rule and giving it to their federal colleagues. It was not until the case of Mapp v. Ohio, 367 U.S. 643 (1961), that the exclusionary rule was deemed to apply to state courts as well.
United States v. Place, 462 U.S. 696 (1983), is a decision by the Supreme Court of the United States in which the Court held that it does not violate the Fourth Amendment to the U.S. Constitution for a trained police dog to sniff of a person's luggage or property in a public place.
Atwater v. Lago Vista, 532 U.S. 318 (2001), was a United States Supreme Court decision which held that a person's Fourth Amendment rights are not violated when the subject is arrested for driving without a seatbelt. The court ruled that such an arrest for a misdemeanor that is punishable only by a fine does not constitute an unreasonable seizure under the Fourth Amendment.
In United States law, the Aguilar–Spinelli test was a judicial guideline set down by the U.S. Supreme Court for evaluating the validity of a search warrant or a warrantless arrest based on information provided by a confidential informant or an anonymous tip. The Supreme Court abandoned the Aguilar–Spinelli test in Illinois v. Gates, 462 U.S. 213 (1983), in favor of a rule that evaluates the reliability of the information under the "totality of the circumstances." However, Alaska, Hawaii, Massachusetts, New York, Vermont, Oregon, and Washington have retained the Aguilar–Spinelli test, based on their own state constitutions.
Suppression of evidence is a term used in the United States legal system to describe the lawful or unlawful act of preventing evidence from being shown in a trial. This could happen for several reasons. For example, if a judge believes that the evidence in question was obtained illegally, the judge can rule that it not be shown in court. It could also refer to a prosecutor improperly or intentionally hiding evidence that does not go with their case and could suggest or prove to the judge or jury that the defendant is not guilty or that (s)he is legally obligated to show the defense. In the latter case, this would be a violation of the 5th amendment to the United States Constitution. Also Rule 3.8 of the ABA Model Rules of Professional Conduct requires prosecutors to "make timely disclosure to the defense of all evidence or information that tends to negate the guilt of the accused or mitigates the offense." This can result in a mistrial in the latter case and/or the dismissal of the prosecutor.
Search incident to a lawful arrest, commonly known as search incident to arrest (SITA) or the Chimel rule, is a U.S. legal principle that allows police to perform a warrantless search of an arrested person, and the area within the arrestee’s immediate control, in the interest of officer safety, the prevention of escape, and the preservation of evidence.
Ker v. California, 374 U.S. 23 (1963), was a case before the United States Supreme Court, which incorporated the Fourth Amendment's protections against illegal search and seizure. The case was decided on June 10, 1963, by a vote of 5–4.
In United States criminal law, the border search exception is a doctrine that allows searches and seizures at international borders and their functional equivalent without a warrant or probable cause. Generally speaking, searches within 100 miles of the border are more permissible without a warrant than those conducted elsewhere in the U.S. The doctrine also allows federal agents to search people at border crossings without a warrant or probable cause. The government is allowed to use scanning devices and to search personal electronics. Invasive bodily searches, however, require reasonable suspicion.
Welsh v. Wisconsin, 466 U.S. 740 (1984), was a 1983 case before the US Supreme Court determining that a warrantless home arrest without exigent circumstances violates the Fourth Amendment protection against unlawful search and seizure.
Arizona v. Gant, 556 U.S. 332 (2009), was a United States Supreme Court decision holding that the Fourth Amendment to the United States Constitution requires law-enforcement officers to demonstrate an actual and continuing threat to their safety posed by an arrestee, or a need to preserve evidence related to the crime of arrest from tampering by the arrestee, in order to justify a warrantless vehicular search incident to arrest conducted after the vehicle's recent occupants have been arrested and secured.
Kentucky v. King, 563 U.S. 452 (2011), was a decision by the US Supreme Court, which held that warrantless searches conducted in police-created exigent circumstances do not violate the Fourth Amendment as long as the police did not create the exigency by violating or threatening to violate the Fourth Amendment.
Immigration and Naturalization Service v. Delgado, 466 U.S. 210 (1984), was a United States Supreme Court decision on the limits of worksite enforcement by immigration agents. Specifically, the Court ruled that factory raids by the Immigration and Naturalization Service (INS) were not illegal seizures under the Fourth Amendment to the U.S. Constitution.
People v. Diaz, 51 Cal. 4th 84, 244 P.3d 501, 119 Cal. Rptr. 3d 105 was a Supreme Court of California case, which held that police are not required to obtain a warrant to search information contained within a cell phone in a lawful arrest. In a sting operation conducted by local police, the defendant, Gregory Diaz, was arrested for the sale of the illicit drug ecstasy and his cellphone, containing incriminating evidence, was seized and searched without a warrant. In trial court proceedings, Diaz motioned to suppress the information obtained from his cellphone, which was denied on the grounds that the search of his cellphone was incident to a lawful arrest. The California Court of Appeal affirmed the court's decision and was later upheld by the California Supreme Court. In 2014, the United States Supreme Court overruled that position in Riley v. California and held that without a warrant, police may not search the digital information on a cellphone that has been seized incident to arrest.
Riley v. California, 573 U.S. 373 (2014), is a landmark United States Supreme Court case in which the court ruled that the warrantless search and seizure of the digital contents of a cell phone during an arrest is unconstitutional under the Fourth Amendment.
