In Devenpeck v. Alford, No. 03-710 (Dec. 13, 2004), the Supreme Court held that a warrantless arrest by a police officer is reasonable even if the offense establishing probable cause is not "closely related" to the conduct the arresting officer gives the defendant as the reason for the arrest at the time of arrest. The Court noted that under Whren v. United States, 517 U.S. 806 (1996), an arresting officer’s subjective reason for making an arrest is irrelevant to probable cause. What matters is whether, given the facts known to the officer, there is probable cause to believe that a crime has been or is being committed. The Court noted that a "closely related offense" test for probable cause would have the perverse effect of causing officers to cease giving reasons for arrest, or to cite every conceivable reason for the arrest.
