Also known as: knock and announce rule · knock-and-announce · knock and announce · knock-and-announce requirement
Written by attorneys · grounded in primary & secondary sources — see below
A Fourth Amendment rule requiring officers executing a search warrant at a dwelling to knock, announce their presence and purpose, and wait a reasonable time before forcing entry. The rule protects occupants' privacy, dignity, property, and safety from sudden intrusions. Officers may dispense with compliance upon reasonable suspicion that announcement would be dangerous, futile, or lead to evidence destruction.
Detectives approached Kendra Kowalski's apartment with probable cause to believe she was destroying digital files tied to an extortion scheme. They knocked and announced their presence. Moments later they heard typing and a shredder activate. Officers forced entry without a warrant and seized the computers. The court upheld the entry because the sounds supplied an objectively reasonable belief of imminent destruction that arose after a lawful announcement.
Officers with a valid warrant for Kinetic Solutions' office used a battering ram to enter without knocking or announcing. They seized servers containing evidence of data theft. The company moved to suppress the evidence solely on the knock-and-announce violation. The court denied the motion because exclusion is unavailable as a remedy for that type of violation even when the entry was forceful.
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Officers responded to a loud fight inside Kai Kwon's home. One officer opened the screen door, yelled 'police,' and stepped inside after no one responded. The disturbance ended once the announcement was heard. The court found no knock-and-announce violation because the verbal identification served the same protective function as a knock under the chaotic circumstances.
Detectives lacked an arrest warrant when they entered Kelvin Kimura's apartment to arrest him for check fraud. They walked through an unlocked side door without knocking or announcing and found Kimura on the phone. The court suppressed statements made after the entry because, absent exigent circumstances, officers must obtain a warrant before entering a suspect's home to effect an arrest.
Officers had probable cause that Kelsey Kirk was selling narcotics from her apartment. They knocked, announced, and then secured the premises from the outside while obtaining a warrant. They prevented Kirk from re-entering until the warrant arrived. The court upheld the temporary seizure because it was a reasonable means to preserve evidence while complying with the warrant requirement.
After arresting Kamala Krishnan for drunk driving, officers sought a warrant before drawing her blood. They did not rely on a categorical claim that alcohol dissipation always creates an exigency. The court held that the natural dissipation of alcohol does not automatically excuse the warrant requirement in every case.
No. The exclusionary rule does not apply to violations of the knock-and-announce requirement during execution of a valid warrant. The interests protected by the rule, such as safety, property, privacy, and dignity, are too attenuated from the later evidentiary use of seized items. Alternative remedies such as civil suits and internal discipline remain available.
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Officers may make a no-knock entry when they have reasonable suspicion that knocking and announcing would be dangerous, futile, or would lead to destruction of evidence. The determination must be made case by case rather than by a blanket exception for an entire category of cases such as drug warrants.
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Yes. When officers lawfully knock and announce and then hear sounds indicating imminent destruction of evidence, they may enter without a warrant. The exigency must not have been created by an actual or threatened Fourth Amendment violation by the officers themselves.
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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…