Whether police impermissibly create an exigency, and therefore may not rely on the exigent-circumstances exception, when their lawful knock and announcement of identity foreseeably lead occupants to destroy evidence.
Holding
No. Police may rely on exigent circumstances unless they created the exigency by engaging in, or threatening to engage in, conduct that violates the Fourth Amendment.
Reasoning
Warrantless home searches are presumptively unreasonable, but the Fourth Amendment ultimately asks whether a search is reasonable. A recognized exception permits entry when an exigency, including the imminent destruction of evidence, makes obtaining a warrant impracticable. The police-created-exigency doctrine must therefore be tied to the constitutional reasonableness of the officers' conduct before the exigency arose.
The Court adopted an objective rule: officers may make a warrantless entry to prevent the destruction of evidence if they did not create the exigency through an actual or threatened Fourth Amendment violation. This approach parallels the plain-view doctrine, under which officers may seize evidence they expect to find so long as they lawfully reached the vantage point from which they saw it.
The Court rejected a bad-faith test because Fourth Amendment reasonableness generally does not depend on an officer's subjective motive. It also rejected a reasonable-foreseeability test because police activity often causes suspects to fear detection, and courts could not reliably determine how foreseeable destruction of evidence was in rapidly unfolding encounters.
The Court further rejected rules that fault police for failing to obtain a warrant as soon as probable cause exists or for using tactics a court later considers inconsistent with ideal police practice. Officers have no constitutional duty to stop investigating at the first moment probable cause arises; they may seek information, ask for consent, gather stronger evidence, or preserve an investigation's confidentiality.
King's proposed rule—that police create an exigency whenever their manner of knocking or speaking would make a reasonable person believe entry was imminent—was also too vague and impractical. Officers may knock forcefully and identify themselves loudly without violating the Fourth Amendment, and residents remain free not to answer the door or consent to entry.