In law, a witness is someone who, either voluntarily or under compulsion, provides testimonial evidence, either oral or written, of what they know or claim to know.
A search warrant is a court order that a magistrate or judge issues to authorize law enforcement officers to conduct a search of a person, location, or vehicle for evidence of a crime and to confiscate any evidence they find. In most countries, a search warrant cannot be issued in aid of civil process.
An arrest warrant is a warrant issued by a judge or magistrate on behalf of the state, which authorizes the arrest and detention of an individual, or the search and seizure of an individual's property.
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."
United States v. Leon, 468 U.S. 897 (1984), was a United States Supreme Court case in which the Court established the "good faith" exception to the Fourth Amendment exclusionary rule.
Cory Jermaine Maye is a former prisoner in the U.S. state of Mississippi. He was originally convicted of murder in the 2001 death of Prentiss, Mississippi, police officer Ron W. Jones, during a drug raid on the other half of Maye's duplex. Maye has said he thought that the intruders were burglars and did not realize they were police. He pleaded not guilty at his trial, citing self-defense. Nevertheless, Maye was convicted of murder and was sentenced to death. Maye's case attracted little attention until late 2005, when Reason magazine senior editor and police misconduct researcher Radley Balko brought it to light on his blog The Agitator. Balko's research raised several questions about Maye's conviction and in particular about the reliability of medical examiner Steven Hayne, who performed the autopsy on Jones and testified at the trial. According to Maye's supporters, his conviction also brought up issues such as the right to self-defense, police conduct in the War on Drugs, racial and social inequities in Mississippi and whether he received competent legal representation.
Illinois v. Gates, 462 U.S. 213 (1983), is a Fourth Amendment case. Gates overruled Aguilar v. Texas and Spinelli v. United States, thereby replacing the Aguilar–Spinelli test for probable cause with the "totality of the circumstances" test.
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.
Kolender v. Lawson, 461 U.S. 352 (1983), is a United States Supreme Court case concerning the constitutionality of vague laws that allow police to demand that "loiterers" and "wanderers" provide "credible and reliable" identification.
Wilson v. Arkansas, 514 U.S. 927 (1995), is a United States Supreme Court decision in which the Court held that the traditional, common-law-derived "knock and announce" rule for executing search warrants must be incorporated into the "reasonableness" analysis of whether the actual execution of the warrant is/was justified under the 4th Amendment. The high court thus ruled that the old "knock and announce" rule while not a hard requirement, was also not a dead letter.
Franks v. Delaware, 438 U.S. 154 (1978), is a United States Supreme Court case dealing with defendants' rights to challenge evidence collected on the basis of a warrant granted on the basis of a false statement. The court held that where a warrant affidavit contains a statement, necessary to the finding of probable cause, that is demonstrated to be both false and included by an affiant knowingly and intentionally, or with reckless disregard for the truth, the warrant is not valid.
Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009), is a United States Supreme Court case in which the Court held that it was a violation of the Sixth Amendment right of confrontation for a prosecutor to submit a chemical drug test report without the testimony of the person who performed the test. While the court ruled that the then-common practice of submitting these reports without testimony was unconstitutional, it also held that so called "notice-and-demand" statutes are constitutional. A state would not violate the Constitution through a "notice-and-demand" statute by both putting the defendant on notice that the prosecution would submit a chemical drug test report without the testimony of the scientist and also giving the defendant sufficient time to raise an objection.
Marcus v. Search Warrant, 367 U.S. 717 (1961), full title Marcus v. Search Warrant of Property at 104 East Tenth Street, Kansas City, Missouri, is an in rem case decided by the United States Supreme Court on the seizure of obscene materials. The Court unanimously overturned a Missouri Supreme Court decision upholding the forfeiture of hundreds of magazines confiscated from a Kansas City wholesaler. It held that both Missouri's procedures for the seizure of allegedly obscene material and the execution of the warrant itself violated the Fourth and Fourteenth amendments' prohibitions on search and seizure without due process. Those violations, in turn, threatened the rights protected by the First Amendment.
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.
United States v. Janis, 428 U.S. 433 (1976), was a Supreme Court Case that found Max Janis and Morris Levine guilty of illegal bookmaking activities in Los Angeles in a 5-3 ruling. The two were arrested for the crime in November 1968. Appealing on the grounds of unconstitutionally seized evidence, Janis and Levine were heard by the 9th Circuit Court of Appeals in 1973. The case was ultimately heard by the Supreme Court in 1975, and the two were found guilty in 1976. More importantly, the case established that the exclusionary rule does not apply to civil cases where evidence is unconstitutionally seized by a state officer but used by a federal institution.
United States v. Watson, 423 U.S. 411 (1976), was a case decided by the Supreme Court of the United States that decided that a warrantless arrest in public and consenting to a vehicle search did not violate the Fourth Amendment.
Ybarra v. Illinois was a decision of the U.S. Supreme Court which ruled that a warrant can not be used to search an unnamed individual unless the warrant mentions that unnamed parties are involved or exigent circumstances are shown to exist.
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.
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."
Stone v. Powell, 428 U.S. 465 (1976), was decision of the Supreme Court of the United States that limited which claims of Fourth Amendment violations could be made by state prisoners in habeas corpus petitions in federal courts. Specifically, a claim that the exclusionary rule had been broken would be barred if state courts had already given it a full and fair hearing. The decision combined two cases that were argued before the Supreme Court on the same day with similar issues, one filed by Lloyd Powell and the other, titled Wolff v. Rice, filed by David Rice.
