Geofence search warrant was constitutionally overbroad where law enforcement failed to sufficiently narrow the search parameters to avoid unnecessary infringement on the privacy rights of uninvolved third parties. A geofence warrant is an official request by law enforcement to access device location data gathered by large tech companies like Google. This data is typically anonymized, but it can be used in conjunction with other investigative techniques to tie devices to specific users. Here, defendants were identified as suspects in a murder investigation after a geofence search warrant directed to Google revealed that cell phones connected to defendants were in several of the same locations as the victim on the day of his murder. After their motions to quash and suppress evidence were denied, defendants entered guilty and no contest pleas. They appealed. Held: Affirmed (under the good faith exception). In determining validity of a warrant, courts examine probable cause, particularity, and overbreadth. Although the warrant in this case was supported by probable cause, it was overbroad. The warrant authorized the identification of any individual within six large search areas, without any particularized probable cause as to each person or their location, and neither the search boundaries nor the times designated in the geofence warrant were as narrowly tailored as they could have been given the information available at the time. In authorizing search of more than 20 acres total over a cumulative period of more than five hours in residential and commercial areas, the warrant allowed a location-specific identification of thousands of individuals for whom no probable cause existed.

Geofence warrant lacked sufficient particularity because it provided law enforcement with unbridled discretion regarding whether or how to narrow the initial anonymized list of users identified by Google. The warrant set forth a three-step process by which Google could respond to the request for information. Google would initially provide an anonymized list of devices found within the search area (step one). Law enforcement could then review the list and request additional information—even if the additional information fell outside the initial geographic and temporal search parameters (step two), and could then demand identifying information for all devices law enforcement deemed relevant to the investigation (step three). Steps two and three allowed law enforcement to enlarge the search without any objective criteria and failed to place any meaningful restriction on the discretion of law enforcement officers to determine which accounts would be subject to further scrutiny or deanonymization, rendering the warrant invalid.

The denial of defendant’s suppression motion was upheld because the officers reasonably relied on the geofence warrant in good faith. Defendants argued the good faith exception to the exclusionary rule should not apply because it was obvious the warrant did not satisfy the particularity requirement. However, at the time law enforcement officers sought and executed the search warrant, geofence warrants were still a novel investigative tool, and there were no published cases anywhere in the country, let alone California, analyzing the constitutionality of geofence warrants. The officers were not objectively unreasonable in believing the warrant was valid, even if the issue, upon close legal examination, was not a particularly close one.

The geofence warrant’s failure to specify any individual’s name or other identifying information did not render it invalid under the California Electronic Communications Privacy Act (CalECPA). Any warrant issued pursuant to CalECPA must “describe with particularity the information to be seized by specifying, as appropriate and reasonable, . . . the target individuals or accounts” and “the applications or services covered.” Here, the warrant described the target individuals and accounts with the greatest degree of particularity available to the investigators—individuals whose devices were located within the search boundaries at certain times. This was sufficient to comply with CalECPA’s particularity requirement. [Editor’s Note: The court did not address defendants’ argument that the good faith exception to the exclusionary rule does not apply to a violation of CalECPA.]

The full opinion is available on the court’s website here: https://www.courts.ca.gov/opinions/documents/B318310.PDF