Also known as: knock and announce doctrine · knock-and-announce rule · knock and announce rule · knock and announce · knock-and-announce requirement
Written by attorneys · grounded in primary & secondary sources — see below
A Fourth Amendment requirement that officers executing a search or arrest warrant knock and announce their presence and purpose before forcibly entering a dwelling. Officers may dispense with the requirement only upon reasonable suspicion that knocking would be dangerous, futile, or would lead to the destruction of evidence. The rule protects interests in life, property, privacy, and dignity during the manner of entry.
Officers approached Kristopher Kurtz's apartment after tracing a drug sale to the unit. They knocked and announced their presence, then immediately heard footsteps and a toilet flushing. Believing evidence was being destroyed, the officers forced entry without a warrant and seized narcotics. The entry was upheld because the sounds created an objectively reasonable belief of imminent destruction that arose after a lawful knock.
Kwame Kofi operated a trading firm under investigation. Agents with a valid warrant burst through the office doors without knocking or announcing and seized records. Kofi moved to suppress the evidence on the ground that the manner of entry violated the Fourth Amendment. The court denied the motion because suppression is unavailable as a remedy even when officers fail to knock and announce before executing a valid warrant.
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Officers suspected Kai Kwon of check fraud and followed him to his residence. Without obtaining an arrest warrant they entered through an unlocked side door and arrested him inside. Kwon moved to suppress statements made after the entry. The court granted the motion because officers must obtain a warrant to enter a suspect's home for a nonemergency arrest absent exigent circumstances.
Officers responding to a disturbance at Kimberly Knox's home saw a juvenile strike an adult inside the kitchen. They entered without a warrant to stop the ongoing violence. Knox later challenged the entry. The court upheld the officers' actions because they possessed an objectively reasonable basis to believe an injured person needed immediate assistance.
Officers arrested Kelsey Kirk for drunk driving and sought a warrantless blood draw to measure alcohol content. Kirk refused consent and moved to suppress the results. The court held that the natural dissipation of alcohol in the blood does not automatically create exigent circumstances justifying a warrantless search in every case.
Officers had probable cause to believe Kamala Krishnan was selling drugs from her apartment. They prevented her from entering while obtaining a warrant rather than forcing immediate entry. Krishnan challenged the temporary seizure of the premises. The court upheld the officers' conduct because the restraint was reasonable in duration and scope under the circumstances.
No. The exclusionary rule does not apply to violations of the knock-and-announce requirement when officers execute a valid warrant. The interests protected by the rule are too attenuated from the use of seized evidence at trial, and the social costs of suppression outweigh any marginal deterrent benefit.
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Officers may dispense with the requirement upon reasonable suspicion that knocking would be dangerous, futile, or would lead to destruction of evidence. The determination must be made case by case rather than through a blanket exception for an entire category of cases.
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No. The requirement applies to the execution of both search warrants and arrest warrants when officers enter a dwelling or equivalent space where an occupant has a reasonable expectation of privacy.
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Yes. Officers may enter without a warrant to prevent imminent destruction of evidence even when the exigency arises after a lawful knock and announcement, provided they did not create the exigency through an actual or threatened Fourth Amendment violation.
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…rule. The Michigan Supreme Court also affirmed. Held: The exclusionary rule does not apply to violations of the knock-and-announce requirement. Majority opinion Opinion of Justice Scalia The common-law principle that law enforcement officers must announce their presence before entering a dwelling has long been part of…