Controversy over geofence searches - privacy issues and legal debates

Imagine that a robbery occurs in a park at night. The police have no suspects: the robber was wearing a mask and left no obvious clues. However, the victim noticed the robber carried a cell phone. In such a situation, the police might seek a geofence search warrant.

A geofence search uses latitude and longitude coordinates to draw an imaginary boundary around a crime scene--a geographical fence--and then asks companies like Google to identify all cell phones using their applications that were inside the fenced area during a defined time window when the crime occurred. If our hypothetical robbery took place at 10:05 p.m. at a specific park bench, the geofence warrant might describe a circular area of 100 meters radius from that bench, for a time period from 9:55 p.m. to 10:15 p.m. (10 minutes on either side of the crime), and require Google to identify all cell phones using its applications that were within that area during that timeframe.

Geofence searches rely on three things: (a) technology now allows precise tracking of cell phone locations to within a few meters; (b) most people keep their cell phones on their persons most of the time; and (c) tech companies voraciously track their users' locations and, for commercial purposes, retain databases containing that historical location information.

Such searches can provide powerful information. In our example, Google might identify three users that were within the fenced area during the 20-minute timeframe. One may be the victim. The other two persons potentially are worth investigating. One of them may be the robber; and both are at least potential witnesses who may have relevant evidence. (Technically, Google initially provides de-identified information for all devices within the geofence. The police must then separately request Google provide specific user identities for the subset of devices believed relevant.) Note, though, that it is possible the robber had Google's Location History turned off, and so would not be identified.

There is a potential difficulty with geofence searches under the Fourth Amendment. These searches do not name a specific person who is a suspect. Rather, the searches seek to identify anyone who was within a defined area during a certain time period. They are a limited electronic dragnet.

So, are geofence searches lawful? The U.S. Supreme Court likely will have to answer that question. This is because two U.S. Court of Appeals have recently issued opposing opinions on geofence searches. In August, the Fifth U.S. Circuit Court of Appeals ruled that geofence searches are unconstitutional violations of the Fourth Amendment. United States v. Smith, 110 F.4th 817, 838 (5th Cir. 2024). But in July, the Fourth U.S. Circuit Court of Appeals held that when police obtain Google Location History data, that is not a search, because users voluntarily give their location data to Google, and thus have no reasonable expectation of privacy in it. United States v. Chatrie, 107 F.4th 319, 339 (4th Cir. 2024). These two positions are irreconcilable.

In Smith, a U.S. Postal Service driver in rural Mississippi was pistol whipped and robbed at gunpoint while collecting mail bags containing cash receipts from four post offices. The robbery occurred at 5:20 p.m. at the back door of the small Lake Cormorant Post Office. The robber fled with mailbags containing $60,706. Security video from a nearby farm showed that the robber exited a white SUV and waited behind the Post Office, while appearing to talk on a cell phone until the postal driver arrived. A red Hyundai appeared to be coordinating with the white SUV.

Lacking any leads, the police sought a geofence warrant for Google location data. The warrant specified a rectangular area around the Lake Cormorant Post Office, encompassing 98,192 square meters (roughly the size of 18 football fields), for the 60 minutes between 5:00 p.m. and 6:00 p.m.

The warrant was effective. Google's information showed that three devices were within the fenced perimeter during the timeframe: two of the devices belonged to defendants Jamarr Smith and Gilbert McThunel; the third device was determined to be irrelevant. With initial suspects identified, additional investigation revealed phone calls between Smith and McThunel during the time of the robbery, and also identified a third suspect, Iroko Ayedele. (His cell phone had been in communication with Smith and McThunel's, but he had been located outside the geofence perimeter.)

The government charged the three defendants with conspiracy to commit robbery and robbery. Defendants moved to suppress all evidence resulting from the geofence search. The district court denied the motion. Defendants were then convicted after a four-day jury trial. Among other evidence, cell phone records (obtained by separate warrant, after the geofence data had identified the two initial suspects), showed that on the day of the robbery the three defendants had traveled from Batesville to Lake Cormorant and back, a drive of 58 miles each way. This was significant because Lake Cormorant has a population of only 2,030 people and, as the district court noted, "is located in a rural part of the state with little to no attractions that would draw an outsider to the town." United States v. Smith, 2023 WL 2703608 at *3 (N.D. Miss. March 29, 2023).

On appeal, the Fifth Circuit ruled the geofence search was unconstitutional. The court first held that the defendants had a reasonable expectation of privacy in their location data held by Google. The court dismissed the prosecution's argument that the defendants had affirmatively "opted in" to having Google track their Location History, and thus had waived any reasonable expectation of privacy. Instead, the court reasoned that because a large number of users allow Google to track their locations, this shows the process of opting in is involuntary. The "fact that approximately 592 million people have 'opted in' to comprehensive tracking of their locations [by Google] itself calls into question the 'voluntary' nature of this process." Smith, 110 F.4th at 836.

Having established that defendants had a privacy interest in their location data, the court then categorically rejected geofence searches. The court held that geofence warrants are reviled general warrants under the Fourth Amendment. General warrants (which provided one motivation for the Revolutionary War against Britain) are "warrants that specify only an offense, leaving to the discretion of the executing officials the decision as to which persons should be arrested and which places should be searched," and they are "plainly unconstitutional." Id. (cleaned up).

The Fifth Circuit reasoned that geofence warrants are like general warrants because "the quintessential problem with [geofence] warrants is that they never include a specific user to be identified, only a temporal and geographic location where any given user may turn up." Id. at 837. The court concluded, "we hold that geofence warrants are general warrants categorically prohibited by the Fourth Amendment." Id. at 838. (Despite this, the court then affirmed defendants' convictions, applying the good-faith exception rule, since geofence warrants are novel, with a "dearth of court precedent." Id. at 839-840.)

There may be a flaw, however, in Smith's analogy that geofence warrants are like general warrants. Colonial-era general warrants were abhorrent because they allowed British officials to search any houses they liked, in their sole discretion. Thus, the "central objectionable feature" of general warrants "was that they provided no judicial check on the determination of the executing officials that the evidence available justified an intrusion into any particular home."  Steagald v. United States, 451 U.S. 204, 220 (1981). In contrast, geofence warrants are limited to a defined location, for a defined time period. Unlike general warrants, the police cannot unilaterally shift a geofence warrant to another location or time.

In contrast to Smith is the Fourth Circuit's holding in Chatrie. That case involved a robbery of the Call Federal Credit Union in Midlothian, Virginia. The robber used a gun and took $195,000 from the vault. The police had no suspects, but the security video showed the robber carried a cell phone.

The police obtained a geofence warrant for Google location data from a 150-meter radius around the bank, for an hour before and after the robbery. They obtained initial information that 19 devices were within the perimeter and narrowed that to three of interest. One of those three phones belonged to defendant Okello Chatrie, who then was indicted for armed robbery of the credit union. After the district court denied his motion to suppress the geofence evidence, Chatrie entered a conditional guilty plea.

On appeal, in a 2-1 decision, the Fourth Circuit majority held that "Chatrie did not have a reasonable expectation of privacy in two hours' worth of Location History data voluntarily exposed to Google." Therefore, the majority ruled the "government did not conduct a search when it obtained this information from Google." Chatrie, 107 F.4th at 325.

The majority first noted that Google's Location History is turned "'off by default,' and must be affirmatively activated by a user." To activate a device, the user must acknowledge a text stating that Location History "saves where you go with your devices." Chatrie had opted-in to Google's Location History. Id. at 331-32. The court pointed out that "two-thirds of active Google users have not enabled Location History," thus showing that "its activation is unnecessary to use a phone or even to use apps like Google Maps." Id. at 331.

Under the third-party doctrine, a person has no legitimate expectation of privacy in information they voluntarily turn over to third parties; the person takes the risk that the information will be conveyed by the third-party to the government. Applying the doctrine, the court ruled that Chatrie "knowingly and voluntarily chose to allow Google to collect and store his location information" and therefore took the risk that Google would convey that information to the government. Thus, he had no reasonable expectation of privacy in his location data. Id. at 332. The Fourth Circuit majority concluded, "[w]e hold that the government did not conduct a Fourth Amendment search when it accessed two hours' worth of Chatrie's location information that he voluntarily exposed to Google." Id. at 339.

At present, therefore, Google geofence searches are illegal in the Fifth Circuit, but are legal in the Fourth Circuit. Until the U.S. Supreme Court resolves the issue, the status of federal geofence searches is uncertain.

California state court practitioners are not bound by opinions of federal Circuit Court of Appeals, though they can be persuasive. State practitioners might look for initial guidance to People v. Meza, 90 Cal. App. 5th 520 (2023). In Meza, the Second District Court of Appeal held that, to be constitutional, geofence warrants (a) must not be overbroad in area or time, and (b) must not give law enforcement unbridled discretion to obtain specific identifying information (implying that a second warrant may be prudent after Google provides initial de-identified information). Meza ruled that a geofence search of "more than 20 acres total over a cumulative period of more than five hours in residential and commercial areas" was overbroad (but nevertheless held that the good faith exception applied so that the evidence should not be excluded). Id. at 541.

Significantly, however, Meza did not resolve whether the defendants had a reasonable expectation of privacy in their Google location data. This was because the prosecution failed to raise that point in the trial court and therefore forfeited the issue. Id. at 535, n. 10. After Chatrie, that issue likely must be addressed.

So where does this leave us? Geofence searches are now a widely-used investigative tool. Smith noted that in 2020 Google received 11,500 geofence warrant requests, and that by "2021 geofence warrants comprised more than 25% of all warrant requests Google received in the United States." Smith, 110 F.4th at 822. Undoubtedly, those numbers have increased. Given the Smith/Chatrie circuit split, the U.S. Supreme Court might be motivated to clarify whether and when geofence searches are legal under the Fourth Amendment.