Under common law knock-and-announce rule, a police officer executing a search warrant generally should not immediately force their way into a residence. Instead, the officer must first knock, identify themselves and their intent, and wait a reasonable amount of time for the occupants to let them into the residence.
When a lawsuit is filed over an officer's entry into a home, a court conducts an inquiry into whether the entry was reasonable. In Wilson v. Arkansas, the Supreme Court held that whether the knock-and-announce principle was adhered to constitutes one factor that a court must consider.
In Hudson v. Michigan, the Supreme Court held that the violation of the knock-and-announce rule does not justify excluding evidence related to the violation of this rule.
In Richards v. Wisconsin, the Supreme Court held that an officer is not required to knock and announce if doing so would be unreasonable. This includes situations in which officers suspect that announcing their presence would be dangerous, futile, or result in the destruction of evidence.
In some jurisdictions, courts may also grant a no-knock search warrant which waives the officer’s knock-and-announce requirement. To obtain this warrant, the warrant applicant usually has to prove the request is reasonably justified to prevent danger, futility, or destruction of evidence. However, if their request is denied, officers may still enter unannounced if they find themselves in a permissible no-knock situation.
[Last updated in June of 2023 by the Wex Definitions Team]