No-knock warrant

In the United States, a no-knock warrant is a warrant issued by a judge that allows law enforcement officers to enter a property without immediate prior notification of the residents, such as by knocking or ringing a doorbell. In most cases, law enforcement will identify themselves just before they forcefully enter the property. It is issued under the belief that any evidence they hope to find can be destroyed during the time that police identify themselves and the time they secure the area, or in the event where there is a large perceived threat to officer safety during the execution of the warrant.

English common law has required law enforcement to knock-and-announce since at least Semayne's case (1604), and in Miller v. United States (1958), the Supreme Court of the United States recognized that police must give notice before making a forced entry. However, in Wilson v. Arkansas (1995) the Court created an exception to prevent the destruction of evidence and in Hudson v. Michigan (2006) the Court, by a 5-4 vote, held the exclusionary rule does not require the suppression of evidence police seize during an illegal forced entry.

According to the United States Department of Justice:

Federal judges and magistrates may lawfully and constitutionally issue "no-knock" warrants where circumstances justify a no-knock entry, and federal law enforcement officers may lawfully apply for such warrants under such circumstances. Although officers need not take affirmative steps to make an independent re-verification of the circumstances already recognized by a magistrate in issuing a no-knock warrant, such a warrant does not entitle officers to disregard reliable information clearly negating the existence of exigent circumstances when they actually receive such information before execution of the warrant.

Oregon state law bans no-knock warrants. In 1994, the Supreme Court of Florida prohibited no-knock warrants. 13 states have laws explicitly authorizing no-knock warrants and in twenty additional states no-knock warrants are routinely granted.

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