A search warrant is a warrant issued by the competent authority authorizing a police officer to search a specified place for evidence even without the occupant’s consent. A search warrant is generally required for a Fourth Amendment search, subject to a few exceptions. In Katz v. United States, 389 U.S. 347 (1967), the Supreme Court held that searches conducted outside the judicial process, without prior approval are prohibited under the Fourth Amendment, with a few detailed exceptions
“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.”
Obtaining a Search Warrant
Only judges and magistrates may issue search warrants. In Coolidge v. Hampshire, 403 U.S. 443 (1971), the Supreme Court held that a warrant must be issued by a "neutral and detached" judge capable of determining whether probable cause exists. To obtain a warrant, law enforcement officers must show that there is probable cause to believe a search is justified. Officers must support this showing with sworn statements (affidavits), and must describe in particularity the place they will search and the items they will seize. In Groh v. Ramirez, 540 U.S. 551 (2004), the Court held that a warrant that lacks accurate information as to what will be searched is improper, and that a search which happens pursuant to that warrant is unlawful and violates the Fourth Amendment.
In Illinois v. Gates, 462 U.S. 213 (1983), the Supreme Court held that when deciding whether to issue the warrant, a judge must must consider the totality of the circumstances, including an informant's veracity, reliability, and basis of knowledge.
When issuing a search warrant, the judge may restrict how and when the police conduct the search. In Zurcher v. Stanford Daily, 436 U.S. 547 (1978), the Supreme Court allowed the police to search a student newspaper. The newspaper was not implicated in any criminal activity, but police suspected it had photographic evidence of the identities of demonstrators who assaulted police officers. However, some jurisdictions responded by passing laws restricting or forbidding these kinds of searches, such as when California's legislature created CA Penal Code § 1524.
When determining whether the actual search violates the Fourth Amendment, courts will use a reasonableness test. Warrantless police conduct may comply with the Fourth Amendment, provided that the conduct is reasonable under the circumstances. In Maryland v. Garrison, 480 U.S. 79 (1987), the warrant indicated that “the third floor apartment” was to be searched. Howevere, there were two apartments on the third floor. As such, the search of both apartments was considered reasonable.
Exceptions to the Warrant Requirement
The Supreme Court has also created some exceptions to the warrant requirement. This is seen in the hot pursuit exception (as established in Warden v. Hayden, 387 US. 294 (1967)), and the automobile exception (as demonstrated in Caroll v. United States, 267 U.S. 132 (1925), but narrowed in Arizona v. Gant, 556 U.S. 332 (2009)).
Similarly, the Supreme Court has established that searches which are incident to the warranted search do not necessarily violate the Fourth Amendment. In Michigan v. Summers, 452 U.S. 692 (1981), the Court held that a warrant--based on probable cause--to search for contraband also implicitly grants the police to detain the occupants of the premises during the search. Additionally, when determining whether to apply the exclusionary rule in light of police deviations from warrant restrictions, courts consider whether the actual search was unreasonable.
Normally, law enforcement officers executing a search warrant may not immediately force their way into a residence. Instead, they must first knock and announce their identity and intent. Then, they must wait a reasonable amount of time to allow an occupant to open the door. Only after waiting may the police force entry. This “knock-and-announce rule” is one of the factors a court must consider in its reasonableness test, as stated in Wilson v. Arkansas, 514 U.S. 927 (1995).
Police may disregard the knock-and-announce rule when it is reasonable to do so. In Richards v. Wisconsin, 520 U.S. 358 (1997), the Supreme Court held that a no-knock entry is justified when, under the circumstances, knocking and announcing their presence "would be dangerous or futile, or that it would inhibit the effective investigation of the crime."
An anticipatory warrant grants police officers a warrant that becomes valid after some future triggering condition occurs. Courts reserve these types of warrants for situations in which police have probable cause that at some future time evidence in a particular location will become available. In United States v. Grubbs, 547 U.S. 90 (2006), the Supreme Court upheld anticipatory warrants, holding that a warrant need not set out the conditions that trigger it, only the place to be searched and the persons or things to be searched for.
Warrants for Electronic Data
Police officers may obtain warrants to seize and search electronic storage media or electronically stored information. Since December 1, 2009, Rule 41 of the Federal Rules of Criminal Procedure governs these searches. The rules allow officers to copy seized material for later review. The new version of Rule 41 governing these searches also allows police officers to plant tracking devices on persons or property.
Timing of Searches (under construction)
Generally, only under special circumstances may police officers execute search warrants at night. Different jurisdictions use different definitions of “nighttime.” For example, federal law enforcement officers must normally start searches between 6:00 a.m. and 10:00 p.m. See Rule 41 of the Federal Rules of Criminal Procedure. In practice, the special circumstances exception applies most frequently in drug cases.
Extent of Searches
When conducting a search, police may only search the places and people listed on the search warrant, and may only search for the sought-after evidence. Accordingly, officers may only search places where they might reasonably find the evidence. For example, officers searching for a rifle may not look in a small jewelry box.
Search warrants may authorize police to search specific, named people found at the targeted location. However, officers executing a search warrant may detain anyone present during the search. Furthermore, if officers find sufficient evidence to arrest someone present, they may arrest and search that person, even if the person was not listed on the warrant. (See "Incidental Searches" above).
Post-Search Procedural Safeguards
Rule 41(f)(1) of the Federal Rules of Criminal Procedure discusses the federal requirements for returning a warrant. Most jurisdictions impose additional post-search procedural safeguards. For example, many jurisdictions require officers to return a copy of the search warrant to the judge after executing it. This return copy must include information about the search, including a list of what was seized. Similarly, most jurisdictions require officers to give a receipt for seized property.