The “knock-notice” or “knock-and-announce” rule derives from the Fourth Amendment’s protection against unreasonable searches and seizures. In general, even if officers have a search or arrest warrant that justifies entering a home, they must announce themselves and their purpose before intruding. The Fourth Amendment requires this notice, as do many state laws. Only after the officers have been refused entry or waited a sufficient amount of time without receiving a response can they enter a home without permission, either with or without force. But, as with practically all legal rules, there are exceptions.
Police officers must usually announce themselves and either explicitly or implicitly request entrance into a home. (An implicit request might take the form of, “Police—we’re here to execute a search warrant!”) But courts aren’t sticklers when it comes to what officers must communicate. As long as officers take reasonable measures to broadcast their presence, judges are likely to find that they satisfied the notice requirement. That’s true even if those inside the home didn’t hear and were otherwise unaware of the officers’ request for admittance. For example, a federal court in Ohio found that, even though the only resident who was present in the home didn’t hear officers knock and declare themselves, those officers properly entered. (United States v. Thompson, 667 F. Supp. 2d 758 (S.D. Ohio 2009).)
In most instances, officers can’t legally knock on a front door and yell, “Police—open up!” while simultaneously battering their way through it. They have to wait. How long, you ask? As with almost all legal questions, the answer depends. In fact, if the circumstances are pressing enough, they might not have to wait at all.
Courts generally require that law enforcement wait a “reasonable” period of time between knock-announcement and barging into a home. But what’s reasonable to one officer or judge might be unreasonable to another. Further complicating the issue is the U.S. Supreme Court’s watering down of the requirement.
In Hudson v. Michigan, the Court observed that officers need not knock and announce if there is a threat of violence or reason to believe providing notice will inspire occupants to destroy evidence. (547 U.S. 586 (2006).) The Court commented that the showing that officers must make to justify ignoring the knock-and-announce rule “is not high.” The result is a general perception that courts rubberstamp forcible residential entry by law enforcement.
That perception isn’t baseless, but courts actually do, from time to time, find that officers have unjustifiably violated the knock-notice rule. For example, in a 2010 opinion, an Indiana appellate court determined that the circumstances weren’t sufficiently “exigent” for the police to have impatiently barged their way into a residence to execute a search warrant. (Lacey v. State, 931 N.E.2d 378 (Ind. Ct. App. 2010).) The prosecution argued that the criminal records of the occupants justified the officers ramming open the front door and declaring themselves only as they were entering. The court disagreed, and therefore found it appropriate to suppress the evidence the officers found after busting into the home.
The Supreme Court has held that knock-and-announce violations don’t require suppression of evidence that officers find after entering a home. (Hudson v. Michigan, supra.) It reasoned that the purposes of the knock-and-announce rule—such as physical safety, property preservation, privacy, and dignity—“have nothing to do with the seizure of the evidence.” Accordingly, it decided that the federal Constitution allows the government to use in court evidence obtained after a knock-notice violation.
But that isn’t the end of the story. State laws and constitutions can provide more personal liberty and privacy protection than their federal counterparts. The result is some state courts finding that judges must suppress evidence after an illegal unauthorized entry. That was the ruling in the above Indiana case. It’s also what an Alaska appellate court found when certain officers had “seriously” violated the knock-and-announce rule. (Berumen v. State, 182 P.3d 635, 636 (Alaska Ct. App. 2008).) In that case, police officers knocked on the door of the defendant’s hotel room for 20 or more seconds without announcing their identity. They then used a hotel key to open the door and enter. They identified themselves as police officers as they were entering, but didn’t disclose their purpose, which was to serve an arrest warrant. The appeals court ruled that the drugs the officers subsequently found were inadmissible in court.
Ultimately, courts vary at least somewhat in their interpretation of the knock-notice rule. And whether a judge will hold that a violation requires evidence suppression depends on the jurisdiction.