Google has weighed in on a court case that will decide the future of a powerful but contentious tool for law enforcement. The company submitted an opinion to the US Supreme Court arguing that geofence warrants are unconstitutional.
A geofence warrant is a form of “reverse warrant” that turns a regular warrant on its head. Police get a regular warrant when they want to target a particular person. With a reverse warrant, police don’t know exactly who they’re looking for. Instead, they ask someone (typically a technology company) for a broad data set about a group of unknown people based on some common behavior. Then they analyze that data set for potential suspects.
With a geofence warrant, that data set is defined by a location and a time window. Law enforcement officials obtain a list of phones that were in that area during that period. Every device that was inside the circle comes back in the results, even if nobody on that list has been suspected of anything. Proximity is the only criterion.
That’s how Okello Chatrie was charged with armed bank robbery in Virginia in 2019: His phone showed up in a geofence warrant covering 17.5 acres (larger than three football fields). He argued that this kind of search isn’t constitutional and shouldn’t have been used as evidence.
In 2024, the Fifth Circuit Court of Appeals agreed with him, overturning a Fourth Circuit ruling. Now prosecutors have taken the case to the Supreme Court, with parties due to make oral arguments on April 27.
The case has seen a flurry of amicus curiae briefs, which are opinions from interested expert parties that have no direct involvement in the case. One of these is from Google, which on Monday urged the justices to consider the geofence warrants unconstitutional because of their broad scope. It has objected to more than 3,000 of them on constitutional grounds in recent months.
Google’s brief stated:
“Many of these overbroad warrants swept in hundreds, sometimes even thousands, of innocent people. State and federal courts have repeatedly granted Google’s motions to quash these overbroad warrants.”
How the database gets built
Although Google is just one of many organizations that filed amicus briefs, its position is especially notable because it has historically collected so much location data. Its Timeline feature (formerly Location History) logs device position via GPS, Wi-Fi networks, Bluetooth, and mobile signals, including when Google apps aren’t being used, according to its policy page.
At the time of the Chatrie warrant, it was recording position as frequently as every two minutes. All of that fed a centralised internal database which held 592 million individual accounts. So responding to any geofence request required Google to search essentially the entire store before producing a single name, according to an analysis by privacy advocacy group EPIC, which also regularly submits amicus briefs on privacy cases.
Google moved Timeline storage from its own servers onto users’ devices in July 2025, closing the door to fresh cloud-based requests against its own systems. But the constitutional question survives for historical data and for any company that has not followed suit.
The warrant that grew and grew
A geofence warrant does not stay fenced, according to a separate brief that the Center for Democracy and Technology (CDT) filed in the case last week. It said Google’s standard response to warrants had three steps. First it would deliver an anonymized list of devices inside the geofence. Then, police could ask for movement data on chosen “devices of interest,” which could track them outside the geographic boundary and beyond the original time window. Finally, again without any further judicial approval, police could ask for subscriber-identifying information for whichever devices police chose to unmask.
In the Chatrie case, positioning data was imprecise enough that, as the district court found, the warrant may have included devices outside the intended area. According to the CDT brief:
“The Geofence Warrant could have captured the location of someone who was hundreds of feet outside the geofence.”
The CDT argues in its brief that this can expose the privacy of people going about their everyday lives, engaging in legal activities that they might not want others to know about. The warrant that scooped up Chatrie included a hotel and a restaurant.
Some of these requests are far broader. Google successfully challenged a warrant asking for the location history of anyone in large portions of San Francisco for two and a half days, it said. Google complained in its brief:
“No court would authorize a physical search of hundreds of people or places, yet geofence warrants sometimes do so by design.”
What can you do to stop yourself getting swept up in a geofencing search?
If your phone stores detailed location history with Google, that data may be included in geofence warrant responses. Limiting what gets saved can reduce how much location information exists in the first place.
There are two Google settings that matter: Timeline (Location History) and Web & App Activity. Turning off one does not automatically disable the other.
Timeline stores a detailed record of where your device has been, although it’s off by default. Web & App Activity can also log location signals when you use Google services like Search, Maps, or other apps.
Google provides instructions on how to review and disable these settings in its support documentation:
Google has previously settled lawsuits accusing it of misleading users about how location data is stored across these settings, so reviewing both controls is important.
Reverse warrants may not stop at location data
The implications of the case extend well past maps, though. The CDT brief warns that if courts endorse the logic behind geofence warrants, then law enforcement may try to apply the same approach to other large datasets held by technology companies, such as AI chatbot data. That’s a step the DHS has already taken, issuing what has been reported as the first known warrant for ChatGPT user data.
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