A warrantless arrest by a law officer is reasonable under the Fourth Amendment where there is probable cause to believe that a criminal offense has been or is being committed. Whether probable cause exists depends upon the reasonable conclusion to be drawn from the facts known to the arresting officer at the time of the arrest.
Petitioner police officers pulled respondent over on suspicion of impersonating a police officer, and arrested him for violating the state's privacy act after they discovered he was taping their conversation. Respondent filed suit, challenging the constitutionality of his arrest. A jury found for the officers. The U.S. Court of Appeals for the Ninth Circuit reversed, concluding the officers did not have probable cause to arrest. Although respondent's taping of petitioners was not a crime, the appellate court rejected petitioners' claim that there was probable cause to arrest for obstructing or impersonating a law enforcement officer, because those offenses were not "closely related" to the offense invoked by the officer at the time of arrest. Certiorari was granted and the Supreme Court reversed and remanded.
Is an arrest lawful under the Fourth Amendment when the criminal offense for which there is probable cause to arrest is not "closely related" to the offense stated by the arresting officer at the time of arrest?
For purposes of determining whether a warrantless arrest is lawful under the Fourth Amendment, the criminal offense for which there is probable cause to arrest does not have to be "closely related" to the offense stated by the arresting officer at the time of arrest, as: (1) Such a closely-related-offense rule would be inconsistent with Supreme Court precedent, under which an arresting officer's subjective reason for making an arrest does not need to be the criminal offense as to which the known facts objectively provide probable cause.(2) Such a rule would have the perverse consequences that (a) officers would cease providing reasons for arrest; or (b) if that option were to be foreclosed by adoption of a statutory or constitutional requirement, then officers would give every reason for which probable cause could conceivably exist.