Court upholds ‘geofence’ warrant that led to suspect’s cellphone

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The Minnesota Court of Appeals had held that geofence warrants are not categorically prohibited by the U.S. and Minnesota constitutions. In a unanimous ruling, the court held, in State of Minnesota v. Ivan Contreras-Sanchez, that these warrants can be evaluated on a case-by-case basis.

Geofencing uses GPS or RFID technology to make a virtual boundary. Software can be used to determine if a mobile device enters or leaves an area within the boundaries. It is becoming a more common tool used by law enforcement to figure out who was within a “geofence” during a particular timeframe. Law enforcement uses these geofence warrants to get information that can identify those involved in a crime.  Notably, Minneapolis police got a search warrant to order Google to provide account data or anyone within the geographic region of an AutoZone store in south Minneapolis after the building was vandalized following the murder of George Floyd.

A man was reported missing to Minneapolis police on April 7, 2021. Nine days later, the man’s body was discovered face down, with hands tied behind the back, in a drainage culvert. Determining that the cause of death was homicide and that the body was placed in the culvert by an unknown person, the detective began looking for suspects.

The detective sought a geofence warrant to get anonymous information from Google about a cellphone that was in the vicinity of the culvert where the body was found. The geofence warrant application sought location-history data for devices within a 65-foot-wide by 290-foot-long geofence. It encompassed a public roadway and a portion of a right of way ditch.

One device stuck out to the detective, as it “pinged” within the geofence 46 times in 10 minutes on March 29, 2021. This was four days after the decedent was last seen by family and around the time that the decedent was likely assaulted and died. Conversely, other devices were not within the geofence for long, suggesting they passed through at a fast speed.

This also revealed that the owner of the device was at a gas station before entering the geofence. Multiple individuals and a silver SUV were observed in surveillance footage from the gas station. Combined with other knowledge, the detective concluded that the device’s owner was involved in the murder or body disposal. Subsequently, the police obtained a new search warrant to get identifying subscribed information for the owner of the device. Information provided from Google identified the account owner as the defendant. When police tracked down Contreras-Sanchez, and he confirmed that his email address was the same associated with the device, he was arrested.

Contreras-Sanchez was charged with second-degree intentional murder and second-degree unintentional murder while committing a felony. Although Contreras-Sanchez moved to suppress all evidence obtained from the geofence warrant, the court denied the motion. He was found guilty of both counts of second-degree murder and was sentenced to 480 months in prison for second-degree intentional murder.

Contreras-Sanchez appealed, arguing that all geofence warrants are per se unconstitutional or, alternatively, that this geofence warrant satisfied neither federal nor state constitutions.

“The language of this warrant allowed the police to seek whatever information they wanted within a 19,000 square-foot area over a 31-day period,” said Jennifer Workman Jesness, assistant public defender. “The purpose of the warrant was blatantly exploratory.”

“No court, state or federal, has upheld a geofence warrant under these same circumstances,” Workman Jesness added.

“A specific person, of course, has a Fourth Amendment right to be free from unreasonable searches,” asserted Adam Petras, assistant Hennepin County attorney. “But a cellphone, or another device, which is not a living person, which is a non-living item, does not have a Fourth Amendment right, or any constitutional rights for that matter.”

The Minnesota Court of Appeals sided with the state. The court determined that the warrant in Contreras-Sanchez’s case was supported by probable cause, as the warrant application “provided a nexus between the suspected crimes and the cellphone location-history data to be seized.” It concluded that it was reasonable for the issuing judge to conclude that there was a “fair probability” that the deceased was murdered or assaulted and that the geofence warrant would reveal locations of devices owned by the suspects involved in the decedent’s demise.

Nor did the court find the warrant overbroad despite authorizing seizure of anonymous location-history information over a month-long period, citing the nature of a geofence and its rural location. “[A]ny collateral devices tracked by the geofence were only likely to be tracked for the brief moments they drove on the very short stretch of road within the geofence,” the court concluded. “We believe that any such incidental intrusion is reasonable.”

The issue of the constitutionality of geofence warrants has made its way through various state and federal courts. It finally reached the federal court of appeals level. The 4th Circuit has heard oral arguments in U.S. v. Chatrie, in which a man was charged with armed robbery based on Google Sensorvault data obtained through a geofence warrant. In that case, the warrant sought information about Google device or app users within a 17 acre area near the location of a bank robbery.

Aware of privacy concerns, Google announced in December 2023 that users will soon be able to store their location data on their personal devices instead of on Google’s servers. “These changes will gradually roll out through the next year on Android and iOS, and you’ll receive a notification when this update comes to your account,” Google wrote in a blog post dated December 12, 2023.  “Your location information is personal. We’re committed to keeping it safe, private and in your control.”