The way law enforcement tracks people has changed dramatically in the digital age. Police no longer need to follow a suspect in a patrol car to reconstruct where that person has been. Cell phones, automated license plate readers, and other connected technologies can create detailed records of where people and vehicles have been.
On June 29, 2026, the U.S. Supreme Court addressed one important part of that evolving surveillance landscape in Chatrie v. United States, No. 25-112. In a 6-3 decision, the Court held that when police obtain a person’s Google Location History, they conduct a “search” under the Fourth Amendment because people have a reasonable expectation of privacy in their cell-phone location information.
The decision is significant for Oakland criminal defense attorneys because it rejects the idea that digital location information automatically loses Fourth Amendment protection simply because it is stored by a private technology company. It also rejects the government’s argument that a short period of location tracking is necessarily too limited to implicate the Fourth Amendment.
Although Chatrie involved a geofence warrant for cell-phone data rather than automated license plate reader cameras, the reasoning could have important implications for how courts evaluate other forms of networked surveillance, including systems such as Flock Safety.
What Is a Geofence Warrant?
A geofence warrant is a type of investigative demand that seeks information about devices located within a particular geographic area during a particular period of time.
Instead of starting with a known suspect, investigators can start with a location.
For example, if a robbery occurs at 3:00 p.m., police might ask a technology company to identify the phones that were located near the crime scene between 2:30 p.m. and 3:30 p.m. Investigators can then attempt to narrow the list of devices and identify the people associated with them.
That is essentially what happened in Chatrie.
Police investigating a 2019 credit union robbery in Virginia obtained a warrant directing Google to provide information about cell phones located within a 150-meter radius of the credit union. The warrant used a multi-step process: Google first provided anonymized location information for devices within the geofence, investigators narrowed the group, and Google ultimately provided identifying information for individuals remaining on the list.
One of those individuals was Okello Chatrie.
Chatrie challenged the evidence, arguing that the government’s acquisition of his location information constituted a search under the Fourth Amendment.
The Supreme Court agreed.
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The Supreme Court’s Holding in Chatrie
Justice Elena Kagan authored the majority opinion, joined by Chief Justice John Roberts and Justices Sonia Sotomayor, Brett Kavanaugh, and Ketanji Brown Jackson. Justice Neil Gorsuch concurred in the judgment.
The Court’s central holding was straightforward:
Police conducted a Fourth Amendment search when they obtained Chatrie’s cell-phone location information from Google.
The Court relied heavily on its earlier decision in Carpenter v. United States, which recognized a reasonable expectation of privacy in historical cell-site location information.
The Court concluded that Google’s Location History can be even more revealing than traditional cell-site records. According to the opinion, Location History can pinpoint a phone’s location more precisely, record locations much more frequently, and allow investigators to reconstruct a person’s movements retrospectively.
That ability to look backward is particularly important.
Digital surveillance can allow law enforcement to reconstruct where people have been without having observed those movements in real time. A database can effectively become a historical map of a person’s movements.
The “Short Window” Argument Did Not Carry the Day
One of the government’s arguments in Chatrie was that police had obtained only a limited amount of location information.
The Supreme Court rejected the idea that Fourth Amendment protection begins only after surveillance reaches some particular duration.
The Court explained that even short-term monitoring can reveal significant information about a person’s relationships, activities, associations, and movements. The fact that police obtain a relatively small amount of information does not automatically eliminate Fourth Amendment protection.
This part of the decision could become particularly important as defense attorneys challenge other forms of digital surveillance.
A surveillance system does not necessarily become constitutionally insignificant simply because investigators examine a narrow time period.
The question can instead become what information the government obtained, how it obtained it, and what that information allowed investigators to learn.
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The Third-Party Doctrine Does Not Automatically Eliminate Privacy Rights
The government also argued that Chatrie could not claim a reasonable expectation of privacy because his location information was stored by Google.
The Supreme Court rejected that argument.
Building on Carpenter, the Court explained that highly revealing location information is different from ordinary information that a person knowingly provides to a third party. Modern cell-phone users necessarily interact with digital services, and the Court rejected the notion that using those services means a person has effectively surrendered Fourth Amendment protection over detailed location information.
That distinction matters well beyond Google.
Law enforcement increasingly relies on private companies to collect, store, analyze, and provide access to information that can later be used in criminal investigations.
Chatrie signals that the fact that a private company possesses information does not, by itself, answer the Fourth Amendment question.
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What Chatrie Did Not Decide
The Supreme Court’s decision should not be interpreted as holding that every geofence warrant is unconstitutional.
The Court specifically left unresolved whether the particular warrant used in Chatrie’s case satisfied the Fourth Amendment’s requirements for probable cause and particularity. The Court sent those issues back to the lower courts.
That distinction is important for criminal defense cases.
The decision establishes that obtaining this type of location information is a search. It does not mean that every search involving location information is automatically unlawful.
The next questions can include:
- Was there a valid warrant?
- Was probable cause adequately established?
- Was the warrant sufficiently particular?
- How broad was the geographic area?
- How long was the requested surveillance period?
- What information did investigators initially obtain?
- Did police receive identifying information about people who were not suspects?
- Did investigators expand the search beyond the scope authorized by the warrant?
- Did officers use the information for purposes beyond those authorized?
- Does an exception to the warrant requirement apply?
- What remedy is available if the search violated the Fourth Amendment?
Those questions could become central to future suppression litigation.
What Does Chatrie Mean for Flock Cameras?
Flock Safety automated license plate reader cameras present a different technological and legal situation from Google’s Location History.
Flock cameras generally capture images of vehicles traveling on public roads and can record information such as license plates and vehicle characteristics. In litigation concerning Norfolk’s Flock system, for example, the record described cameras operating around the clock and capturing passing vehicles on public roadways. The system can then allow law enforcement to search stored information.
That creates an important legal distinction.
A Flock camera does not necessarily track a person’s location in the same way that a smartphone can. The camera is stationary and generally records a vehicle when it passes a particular location.
But a network of cameras can potentially create something more expansive than any individual camera reveals.
If law enforcement can search a large database of historical license-plate observations, investigators may be able to reconstruct a vehicle’s movements across multiple locations and jurisdictions.
That is where the reasoning in Chatrie could become relevant.
From Geofence to Vehicle-Location Searches
Consider a hypothetical criminal investigation.
Police know that a vehicle was allegedly involved in a burglary at 8:00 p.m. They do not know the vehicle’s license plate.
Instead of identifying a suspect first, investigators search a network of automated license plate readers for vehicles that appeared near the crime scene around the relevant time.
They identify several vehicles.
Investigators then search the database for those vehicles’ previous and subsequent locations. They may discover where a vehicle traveled before the crime, where it went afterward, and potentially where it regularly appears.
The investigation has now moved beyond a single photograph.
It has become a retrospective search of a location database.
That does not mean the search is unconstitutional under Chatrie. The Supreme Court did not decide that question.
But it provides defense attorneys with a stronger framework for asking whether the government’s access to large-scale historical location information constitutes a search and, if so, whether that search was reasonable under the Fourth Amendment.
The “Public Road” Argument May Not End the Analysis
Law enforcement may argue that there is no reasonable expectation of privacy in a vehicle traveling on a public road.
That principle has deep roots in Fourth Amendment jurisprudence.
But modern surveillance technology raises a different question: Does the government’s ability to collect and retrospectively search thousands or millions of otherwise ordinary observations change the constitutional analysis?
Seeing a car on a public street is one thing.
Creating a searchable database that can potentially reveal where that car has traveled over an extended period is another.
The distinction is particularly relevant because Chatrie emphasized the government’s ability to use digital databases to reconstruct movements retrospectively and at scale. The Court described Google’s Location History as enabling investigators to reconstruct people’s movements in a way that can facilitate pervasive surveillance.
Defense attorneys may argue that courts should look beyond individual observations and consider the capabilities of the surveillance system as a whole.
The government, meanwhile, is likely to emphasize the differences between cell-phone location records and ALPR data, including the fact that Flock cameras capture vehicles in public places rather than tracking a person inside a home, doctor’s office, or other private location.
Those competing arguments are likely to shape future litigation.
Flock Camera Searches Could Become an Important Suppression Issue
For someone facing criminal charges, the source of the government’s evidence matters.
If investigators identified a defendant based partly on automated license plate reader data, the defense should determine how that information was obtained and used.
Depending on the circumstances, important questions may include:
Was a warrant obtained?
A defense attorney should determine whether investigators obtained a warrant before conducting a retrospective search of ALPR information.
If a warrant was obtained, counsel should examine its language and scope.
What did the warrant authorize?
The warrant may authorize a search for a particular vehicle, location, date, or offense. Investigators’ actual searches should be compared against what the warrant permitted.
How broad was the search?
A request involving one location and a narrow time period is different from a search involving hundreds of cameras, multiple jurisdictions, and months of historical data.
The scope of the search could become highly relevant to a Fourth Amendment challenge.
How was the defendant identified?
A defendant may have been identified through a chain of investigative steps.
For example:
Flock camera → vehicle identification → historical location search → suspect identification → additional investigation → arrest
Defense counsel should examine each step rather than assuming that the final evidence is automatically admissible.
Who accessed the information?
Digital surveillance systems can generate records concerning who accessed data and when.
Those audit records may help determine whether officers conducted searches outside the scope of an investigation or department policy.
How long was the information retained?
Data retention policies can affect both privacy concerns and the defense’s ability to investigate how evidence was obtained.
Counsel may need to examine the applicable law enforcement policy, vendor agreement, retention policy, database records, and search history.
Schmidt v. City of Norfolk Could Become Increasingly Important
The constitutional debate surrounding Flock cameras is already being litigated.
In Schmidt v. City of Norfolk, plaintiffs challenged Norfolk’s use of a Flock Safety automated license plate reader network, arguing that the system’s operation and access to ALPR information violated the Fourth Amendment. The district court ultimately granted summary judgment to the city in January 2026, and the case has proceeded to the Fourth Circuit.
The case illustrates the legal question surrounding networked ALPR surveillance: whether a system consisting of numerous cameras capturing vehicles on public roads becomes constitutionally different when those observations are stored and searchable as a large-scale historical database.
Chatrie does not decide Schmidt.
But the Supreme Court’s recognition that digital location information can implicate a reasonable expectation of privacy provides defense attorneys and civil-rights litigants with additional constitutional principles to consider.
The outcome of future ALPR litigation could have significant consequences for criminal investigations throughout California and the rest of the country.
Why This Matters in California Criminal Defense Cases
For California defendants, these issues can arise in a wide variety of investigations.
Flock or other ALPR information could potentially become relevant in cases involving:
- Robbery
- Burglary
- Homicide
- Drug offenses
- Weapons charges
- Auto theft
- Hit-and-run investigations
- Assault cases
- Kidnapping allegations
- White-collar investigations
- Gang-related investigations
- Other crimes involving alleged travel to or from a location
Location evidence can be powerful for prosecutors because it may appear objective.
But technology-generated evidence still needs to be examined.
A vehicle appearing near a crime scene does not necessarily establish who was driving it. A license plate associated with a vehicle does not necessarily establish who occupied the vehicle. And a database search showing that a vehicle traveled between two locations does not automatically establish what happened at either location.
The defense should examine the technology, the underlying records, the search methodology, and the conclusions investigators drew from the information.
A New Tool for Challenging Digital Surveillance
The significance of Chatrie v. United States may ultimately extend beyond geofence warrants.
The broader constitutional issue is how the Fourth Amendment applies when the government can use privately maintained databases to reconstruct the movements of people who have not necessarily been identified as suspects.
A traditional police investigation might involve an officer seeing a vehicle and writing down its license plate.
A modern surveillance system can potentially allow investigators to search thousands of historical observations from a centralized database.
The Supreme Court’s decision in Chatrie makes clear that courts cannot simply dismiss privacy concerns because the information exists digitally or because a private company stores it.
At the same time, the decision does not automatically make every digital surveillance system unconstitutional.
The legal fight will likely focus on the details: what information was collected, how much information was obtained, how investigators searched it, whether a warrant was required, whether the warrant was sufficiently particular, and whether the search was reasonable.
What Should You Do If Police Used Flock or Location Data in Your Case?
If you are facing criminal charges and believe police used cell-phone location information, geofence data, Flock cameras, automated license plate readers, or another digital surveillance system to identify you, do not assume that the evidence is automatically admissible.
A criminal defense attorney can investigate how law enforcement obtained the information and determine whether constitutional protections may apply.
That investigation may include examining warrants, police reports, search records, database queries, audit logs, vendor records, retention policies, and the chain of evidence used to connect surveillance data to a defendant.
The Supreme Court’s decision in Chatrie gives defendants another important basis for challenging government access to highly revealing digital location information. As surveillance technology becomes more sophisticated, criminal defense attorneys must be prepared to examine not only what the police claim the technology proves, but also whether the government obtained and used that information in a manner consistent with the Fourth Amendment.
Silver Law Firm Can Help Protect Your Rights
Digital evidence can play an increasingly important role in modern criminal investigations. If law enforcement used cell-phone tracking, geofence information, automated license plate readers, or other surveillance technology in your case, the circumstances surrounding that evidence deserve careful examination.
Silver Law Firm represents people facing criminal charges throughout Oakland, San Jose, and the surrounding Bay Area. The firm’s criminal defense attorneys investigate the evidence against their clients and work to protect constitutional rights throughout the criminal process.
If you are under investigation or have been charged with a crime, speak with a criminal defense attorney before discussing your case with law enforcement.
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