Suspectless Searches

18 Pages Posted: 7 Sep 2021 Last revised: 29 Nov 2021

Date Written: September 3, 2021


Traditional searches of persons, houses, papers or effects usually begin with an identified suspect. But today police are increasingly using technology to engage in what might be called suspectless searches—searches that try to identify a perpetrator—using techniques like geofencing, TiVo droning, DNA matching, automated license plate readers, and facial recognition technology. The Fourth Amendment should govern use of such techniques. But application of its reasonableness requirement to suspectless searches should not always require a warrant or probable cause, given the minimal intrusion often associated with them. Instead, the focus in these types of cases should be how to circumscribe the scope of the search consistent with the Fourth Amendment’s particularity mandate and ensure that normal Fourth Amendment constraints are followed when police act on the information they obtain from the suspectless search.

Keywords: geofencing, facial recognition technology, automated license plate readers, aerial surveillance, Carpenter, Jones, Fourth Amendment

Suggested Citation

Slobogin, Christopher, Suspectless Searches (September 3, 2021). Vanderbilt Law Research Paper No. 21-38, Available at SSRN: or

Christopher Slobogin (Contact Author)

Vanderbilt University - Law School ( email )

131 21st Avenue South
Nashville, TN 37203-1181
United States

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