Here, the officers' suspicion that J. L. was carrying a weapon arose not from their own observations but solely from a call made from an unknown location by an unknown caller. The tip lacked sufficient indicia of reliability to provide reasonable suspicion to make a
Terry stop: It provided no predictive information and therefore left the police without means to test the informant's knowledge or credibility. See
Alabama v.
White, 496 U. S. 325, 327. The contentions of Florida and the United States as
amicus that the tip was reliable because it accurately described J. L.'s visible attributes misapprehend the reliability needed for a tip to justify a
Terry stop. The reasonable suspicion here at issue requires that a tip be reliable in its assertion of illegality, not just in its tendency to identify a determinate person. This Court also declines to adopt the argument that the standard
Terry analysis should be modified to license a "firearm exception," under which a tip alleging an illegal gun would justify a stop and frisk even if
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the accusation would fail standard pre-search reliability testing