Also known as: knock-and-announce · knock and announce rule · knocks and announces · knock-and-announce rule
Written by attorneys · grounded in primary & secondary sources — see below
An announcement requirement that officers must satisfy before forcibly entering a dwelling to execute a search or arrest warrant. Officers must knock, identify themselves as police, state their purpose, and wait a reasonable time for a response unless reasonable suspicion supports a no-knock entry because knocking would be dangerous, futile, or would lead to destruction of evidence.
Officers approached Kwame Kofi's apartment with probable cause to believe he was flushing cocaine down the toilet. They knocked and announced their presence. Hearing the toilet flush and hurried footsteps inside, they forced the door and seized the remaining drugs. The entry was upheld because the sounds created an objectively reasonable belief that evidence was being destroyed and the officers had not manufactured the exigency through unlawful conduct.
Deputies executed a valid warrant at Kiana Kwan's farmhouse by kicking in the door without knocking or announcing. They seized ledgers and packaging materials inside. Kiana moved to suppress the evidence on the ground that the manner of entry violated the Fourth Amendment. The court denied the motion because the exclusionary rule does not remedy knock-and-announce violations when officers act under a valid warrant.
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Officers entered Kamala Krishnan's apartment without a warrant or announcement to arrest her for a felony committed in their presence. They had probable cause and reason to believe she was inside. The entry was upheld because the arrest occurred in a public place or under exigent circumstances that excused both the warrant and announcement requirements.
Officers heard a violent altercation inside Kendra Kowalski's home and saw a juvenile strike an adult. They entered without knocking or announcing to stop the ongoing violence. The entry was upheld because the officers had an objectively reasonable basis to believe someone needed immediate assistance and that violence was escalating.
Officers detained Kaito Kato outside his home while obtaining a warrant after observing drug activity. They prevented him from entering to destroy evidence. The detention was upheld because it was a limited restraint supported by probable cause and lasted only as long as reasonably necessary to secure the warrant.
Officers arrested Karina Kovacs for drunk driving and sought a warrantless blood draw because alcohol dissipates rapidly in the bloodstream. They did not knock or announce before entering her home to obtain the sample. The entry was upheld because the natural dissipation of alcohol created exigent circumstances that justified the warrantless intrusion.
No. The exclusionary rule does not apply to knock-and-announce violations because the interests protected by the rule are too attenuated from the evidentiary use of seized items and the social costs of exclusion outweigh its marginal deterrent benefit.
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Officers may enter without knocking when they have reasonable suspicion that knocking would be dangerous, futile, or would lead to the destruction of evidence. The decision must be made case by case rather than by a blanket exception for an entire category of cases.
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Yes. When officers knock and announce and then hear sounds indicating imminent destruction of evidence, they may enter without a warrant if they reasonably believe evidence is being destroyed and did not create the exigency through an actual or threatened Fourth Amendment violation.
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…requisite constitutional (say, warrant or knock-andannounce) compliance. Cf. Mericli, The Apprehension of Peril Exception to the Knock and Announce Rule—Part I, 16 Search and Seizure L. Rep. 129, 130 (1989) (hereinafter Mericli) (noting that some "[d]rug enforcement authorities believe that safety for the police lies in a swift, surprising…