Document ID: ./input/supremecourt_opinions/opinions/boundvolumes/529bv.pdf
Page Number: 350.0

529US1

Unit: $U41

[09-26-01 09:10:16] PAGES PGT: OPIN

Cite as: 529 U. S. 266 (2000)

275

Kennedy, J., concurring

zure. An anonymous telephone tip without more is differ-
ent, however; for even if the ofﬁcer’s testimony about receipt
of the tip is found credible, there is a second layer of inquiry
respecting the reliability of the informant that cannot be pur-
sued.
If the telephone call is truly anonymous, the inform-
ant has not placed his credibility at risk and can lie with
impunity. The reviewing court cannot judge the credibil-
ity of the informant and the risk of fabrication becomes
unacceptable.

On this record, then, the Court is correct in holding that
the telephone tip did not justify the arresting ofﬁcer’s imme-
diate stop and frisk of respondent. There was testimony
that an anonymous tip came in by a telephone call and noth-
ing more. The record does not show whether some notation
or other documentation of the call was made either by a voice
recording or tracing the call to a telephone number. The
prosecution recounted just the tip itself and the later veriﬁ-
cation of the presence of the three young men in the circum-
stances the Court describes.

It seems appropriate to observe that a tip might be anony-
mous in some sense yet have certain other features, either
supporting reliability or narrowing the likely class of inform-
ants, so that the tip does provide the lawful basis for some
police action. One such feature, as the Court recognizes, is
that the tip predicts future conduct of the alleged criminal.
There may be others. For example, if an unnamed caller
with a voice which sounds the same each time tells police on
two successive nights about criminal activity which in fact
occurs each night, a similar call on the third night ought not
be treated automatically like the tip in the case now before
us.
In the instance supposed, there would be a plausible
argument that experience cures some of the uncertainty sur-
rounding the anonymity, justifying a proportionate police re-
sponse.
In today’s case, however, the State provides us with
no data about the reliability of anonymous tips. Nor do we
know whether the dispatcher or arresting ofﬁcer had any