United States v. Smith, 110 F.4th 817

Three defendants were convicted of robbery and conspiracy based mainly on evidence obtained via a "geofence warrant," which sought Google location data for any user in a defined area near the crime scene during the relevant time window.
The crime involved a robbery of a USPS truck in rural Mississippi, and initial leads had not yielded suspects.
Investigators, unfamiliar with geofence warrants and after consulting others, obtained a warrant which allowed Google to search its entire location database for any user near the crime scene at the relevant time, returning anonymized IDs later de-anonymized at investigators' request.
All key evidence (connecting the defendants to the crime) flowed from information obtained through this geofence warrant.
At trial, defendants moved to suppress the evidence, arguing that the warrant was an unconstitutional general warrant, lacking probable cause and particularity, and that the good-faith exception should not apply. The district court denied the motion, citing law enforcement's reasonable reliance on then-novel warrant procedures.
On appeal, the Fifth Circuit held the use of geofence warrants unconstitutional under the Fourth Amendment but affirmed denial of suppression under the good-faith exception due to reasonable law enforcement actions in light of unclear law at the time.

Issue	Appellants' Argument	Government's Argument	Held
Reasonable expectation of privacy in Google Location History data	Users have a reasonable expectation of privacy in location data, citing Carpenter.	Location data was voluntarily given to Google (third-party doctrine), no privacy violation.	Geofence obtaining of location data is a Fourth Amendment search; privacy rights apply.
Are geofence warrants unconstitutional general warrants?	Warrant lacked particularity and probable cause, seeking information on unknown suspects; resembles prohibited "general warrants."	Geofence warrants are limited to a specific time and place tied directly to a known crime.	Geofence warrants are functionally general warrants and categorically unconstitutional under the Fourth Amendment.
Should the good-faith exception to the exclusionary rule apply?	No reasonable officer could rely on a general warrant in good faith, especially given lack of probable cause and particularity.	Law enforcement acted reasonably and sought legal advice when using a novel investigative tool; no bad faith or recklessness.	Good-faith exception applies; suppression of evidence is not warranted.
Was expert testimony regarding Google location data admissible?	Expert unreliable under Daubert; testimony should have been excluded.	Expert qualified and Google Location History derived from accepted geolocation data sources.	District court acted within its discretion; admitted expert evidence.

Carpenter v. United States, 585 U.S. 296 (2018) (holding that obtaining cell-site location information constitutes a search under the Fourth Amendment and generally requires a warrant)
United States v. Leon, 468 U.S. 897 (1984) (establishing the good-faith exception to the exclusionary rule for evidence seized in reasonable reliance on a warrant)
Riley v. California, 573 U.S. 373 (2014) (recognizing the privacy interest in cell phone data and requiring a warrant for most searches)