How Police Use Google to Find Everyone in an Area

A geofence warrant tells Google: give us every phone that was here at this time. Until June 29, 2026, no one could agree on whether that was a search. Now the Supreme Court has.

State of Surveillance

TL;DR: A geofence warrant tells Google to identify every phone that was inside a circle, on a street, near a building, in a set time window. Police do not have a suspect. They draw a radius on a map and ask Google to search its location database and return a list of devices. In Chatrie, that meant searching the accounts of all of Google's "hundreds of millions of users."[2] The Electronic Frontier Foundation calls geofence warrants "the digital equivalent of police going person to person, home to home, without suspicion that any device holder has a connection to a crime."[2] On June 29, 2026, the Supreme Court ruled in Chatrie v. United States that acquiring location data this way is a Fourth Amendment search.[2] That settled the threshold question of whether the Fourth Amendment applies. It did not end the data flows: Google changed how it stores location data, and EFF says mass geofence searches of Google users' location data have not been possible since July 2025, but Google is not the only company collecting location data.[2]

What a Geofence Warrant Actually Is

A geofence warrant is a court order that requires a service provider such as Google to turn over location data from people who carried their phones near a crime scene.[4] The warrant covers anyone and everyone: people inside the area doing ordinary things, suspects and non-suspects alike. Police do not name a target. They name a circle.

The geographic area is small. The warrant in Chatrie covered accounts within 150 meters of the Call Federal Credit Union in Midlothian, Virginia, which was robbed on May 20, 2019.[4] The first request covered 4:20 to 5:20 p.m. that day.[5] EFF describes the area as "several football fields in size" that "encompassed numerous homes, businesses, and a church," covering over 70,000 square meters in a busy area.[2] The accounts swept up are not anyone's alibi. They are the entire population that happened to walk, drive, or live inside the circle.

Google is the main target. While Lyft, Uber, Apple, and Snapchat have all received geofence warrants, the Harvard Law Review Blog describes Google as "the most common recipient and the only one known to respond."[3] Google holds the data in a database it calls "Sensorvault," and Google reported several years ago that geofence warrants made up 25% of all warrants it receives each year, according to EFF.[1]

How the Three-Step Dragnet Works

Geofence warrants are a structured process, not a single query. The warrant in Chatrie, as summarized in the Cornell LII Supreme Court Bulletin, ran in three steps.[4]

Step one: anonymized list. Google provides anonymized Location History data for devices inside the geofence from thirty minutes before to thirty minutes after the crime. In Chatrie, Google provided data from nineteen accounts.[4]

Step two: narrowed list. Police narrow the list of suspect devices and send it back to Google, which provides anonymized location history for those devices from one hour before to one hour after the crime. In Chatrie, Google refused the detective's first request for all nineteen accounts; he narrowed the request to nine, which Google provided.[4]

Step three: identified list. Police narrow the list again, and Google provides identifying information, including usernames. In Chatrie, the detective requested identifying information for three accounts. One of them belonged to Okello Chatrie.[4]

The whole flow runs on a single warrant. The list shrinks at each step. The final unmasked list is the one that sends police to a door. Of the nineteen accounts in step one, three were unmasked, and one belonged to the person charged.

Who Gets Swept In

The collateral damage from a three-step warrant is structural. Everyone in step one is searched before police know who, if anyone, is connected to the crime. EFF's framing: a geofence warrant "turns innocent bystanders into suspects, just for being in the wrong place at the wrong time."[2]

The Harvard Law Review Blog points to what that looks like in practice. Jorge Molina "spent six days in jail and consequently lost his job after he forgot to sign out of Google before lending his phone to a man later arrested for murder."[3] The same piece notes that geofence warrants have turned innocent passersby into suspects, including "a man tracking his bike rides in the vicinity of a burglarized home."[3]

EFF's December 2023 explainer put the underlying problem plainly: "The only 'evidence' supporting a geofence warrant is that a crime occurred in a particular area, and the perpetrator likely carried a cell phone that shared location data with Google."[1]

What the Supreme Court Ruled on June 29, 2026

The Supreme Court decided Chatrie v. United States (No. 25-112) on June 29, 2026. Justice Kagan wrote the majority opinion. She was joined by Chief Justice Roberts and Justices Sotomayor, Kavanaugh, and Jackson. Justice Jackson filed a concurrence, joined by Justice Sotomayor. Justice Gorsuch filed an opinion concurring in the judgment. Justice Alito filed a dissent, joined in part by Justice Thomas and in part by Justice Barrett; Justice Barrett filed a separate dissent.[5]

Bottom line: people have an expectation of privacy in location data that reveals their movements, and even short-term surveillance of those movements is a search subject to the Fourth Amendment.[2] EFF, which had joined the ACLU, the ACLU of Virginia and Georgetown Law's Center on Privacy & Technology in an amicus brief, called it "the first digital surveillance decision by the Court since its landmark 2018 ruling Carpenter v. United States."[2]

The Court did not decide whether the particular warrant in Chatrie was "reasonable" or whether the "good faith" doctrine applied. The case went back to the Fourth Circuit to address those questions.[2] The tool itself was not declared unconstitutional; what changed is that it now counts as a search.

Two passages in the majority opinion will echo past the case. The Court recognized that even shorter-term surveillance of location data can reveal "private matters," including "a wealth of detail about a person's familial, political, professional, religious, and sexual associations."[2] And it captured the practical stakes in a single line: "the point of carrying smartphones is to use what is on them."[2]

Justice Gorsuch, concurring in the judgment, called location data a user's "personal property," no different from the other "effects" the text of the Fourth Amendment explicitly protects.[2] If a future Court builds on that framing, the third-party doctrine has a much harder time surviving in any context.

What Google's December 2023 Change Actually Means

Google's side of this fight is largely over. In December 2023, Google announced three changes to how it treats Location History data.[1]

First, the data is stored by default on the user's device, not with Google in the cloud. Second, it is set by default to delete after three months, where Google had stored it for at least 18 months. Third, if users back up their data to the cloud, Google will "automatically encrypt your backed-up data so no one can read it, including Google."[1]

EFF reported that since July 2025, mass geofence searches of Google users' location data have not been possible.[2] That is the practical effect of the storage change, and it is why Google's role in this story is mostly closed.

But Google is not the only company that collects location data. EFF points to data brokers that collect and aggregate location data from many apps and provide it to police, and to "cell tower dump" warrants that return data on everyone within range of specific cell towers.[2] EFF expects the ruling's recognition that app records are a user's "own" to have broad implications for data generated by other apps on a phone.[2]

How to Keep Your Phone Out of the Next Dragnet

The aim is to make a warrant return nothing for your devices. Google's help page for Timeline, the current name for Location History, says that when Timeline is on, Google can estimate your location with signals like Wi-Fi and mobile networks, GPS, and sensor information. It also says Timeline is off by default.[7]

Turn Timeline off. Google's instructions: go to the "Timeline" section of your Google Account and, at the top, turn Timeline on or off.[7] Google's documentation also warns that if Search Services History or Web and App Activity are on, your Google Account may still save location data as part of your use of other Google sites, apps, and services.[7] Check those settings too.

Delete the data that is already there. Google's Timeline help page says you may have previous Timeline data in your account on any device where you are signed in, and that you can manually delete it anytime.[7]

Audit every app's location access. Weather, social media, and shopping apps often ask for location access. Geofence warrants work because companies have the data; give them less. Set each app to "While Using" or "Never." Some apps will break or nag you for permission. That is the friction working.

Audit every account on the device. The Molina case is the template: he forgot to sign out of Google before lending his phone.[3] Sign out of any Google account on any device you have handed off or stopped using.

The Honest Takeaway

A geofence warrant is a court order that asks a tech company to identify everyone who was near a place at a time, without naming any particular person. Until June 29, 2026, lower courts were split on whether that was even a Fourth Amendment search. The Supreme Court said it is, and sent the case back to the Fourth Circuit on whether the warrant was reasonable and whether the good-faith doctrine saves the evidence.[2]

The structural risk is broader than Google. Google once reported that geofence warrants made up 25% of the warrants it receives each year.[1] Google's storage change closed off mass searches of its own users' location data, but data brokers and cell tower dumps remain.[2] How far lower courts carry the ruling to those other data sources is the open question.

The practical takeaway is the one EFF has pressed for years: turn off Google Timeline, check the other Google settings that save location, audit app permissions, and treat the assumption that your phone is logging everywhere as a starting condition you have to undo. The Constitution now treats this data as protected. The technical settings are still on you.

Sources

  1. EFF, Is This the End of Geofence Warrants? (December 2023)
  2. EFF, Victory! Supreme Court Says Constitution Protects People's Location Data (June 29, 2026)
  3. Harvard Law Review Blog, Much Ado About Geofence Warrants (February 18, 2025)
  4. Cornell LII, Chatrie v. United States, Supreme Court Bulletin (No. 25-112)
  5. Wikipedia, Chatrie v. United States (justices, vote, procedural history)
  6. Cornell LII, Carpenter v. United States (2018), syllabus and opinion
  7. Google Account Help, Manage your Timeline data

Published: October 11, 2026