People tend to carry cell phones with them anywhere they go. What they might not realize is that those phones are in near-constant communication with cell towers and service providers, meaning data about your location is usually available with these providers. Recently, law enforcement agencies and police have been turning to this data to help them find people who committed crimes, but questions about its legality have been challenged in court.
In Chatrie v. U.S. (2026), the U.S. Supreme Court found that police requesting cell phone location data in a “geofenced” area is a search when it comes to the 4th Amendment’s rules. This means that the search needs a warrant. However, the Court did not get to the heart of the issue and decide whether a geofence search is reasonable or allowed, meaning that we still don’t know if this data ultimately can be seized and used against you.
For help with a criminal case, call the Philadelphia criminal defense lawyers at Kenny, Burns & McGill today at (215) 774-5644.
What is Geofence Cell Phone Data?
A geofence is a virtual fence drawn on a map. Like a real fence, it encloses a specific area.
Cell phones are in constant communication with cell towers and service providers, such as Google. Cell phone providers and Google can draw a geofence around an area and pick a specific time frame to find out what cell phones were in that area at that given time.
How Does Geofence Data Work in Criminal Investigations?
The police often request geofence data to find out what cell phones were in the area of a crime at any given time. They usually do this when a crime was committed, but they don’t know who did it.
This allows them to go to a company like Google and say, “Tell us every cell phone that was in this area during this timeframe.” If Google does that, police can potentially find information about cell phone users who were at the site of a protest, in a bank, or near a shooting.
Then, they can reference that data against other data they have to narrow down suspects or potentially give them leads that they could not arrive at through other info they had.
Chatrie v. United States Facts
In the 2026 case, Chatrie v. United States, the U.S. Supreme Court looked at questions around geofence warrants – warrants given to Google or other companies to demand geofence cell phone data.
In that case, the defendant was accused of robbing a bank. The police didn’t know who committed the crime, so they asked Google for geofence data around the bank during the time of the robbery.
The police obtained a warrant, got the data from Google, sorted through it in three steps, and then used that to find and investigate the defendant. They later arrested him.
Previous Laws
Three major legal rules come into play in cases like this, and they were in place before this Chatrie case:
4th Amendment Warrant Requirement
The 4th Amendment of the U.S. Constitution says that the police can only perform a search if they get a warrant and have probable cause. This means they need to go to a judge/magistrate and show them they have sufficient proof that
- A crime was committed
- The location they want to search will turn up evidence of the crime.
Police only need a warrant if what they are doing constitutes a “search.” For example, pulling up alongside your car and looking in the window is not a search, so they do not need a warrant to do it.
Third-Party Doctrine
Usually, for something to be a “search,” there has to be a reasonable expectation of privacy. If the defendant disclosed something to a third party, then it is usually said that there is no expectation of privacy there, so there is no “search.”
For example, it has long been held that throwing something in the garbage means you’re letting the garbage company see it. Courts have held that means you have no further expectation of privacy in it, because you gave it to them.
Carpenter v. United States (2018)
One common way we disclose information to third parties is sharing our cell phone data with the cell phone company. For example, your phone has to be in touch with cell towers to make a call, meaning the cell phone company can loosely tell your location based on your cell phone’s communication records.
The Supreme Court held in 2018 in Carpenter v. United States that even though all of that info is disclosed to a third party, we still have a reasonable expectation of privacy in our cell-site location data. That means that, despite the third-party doctrine, police still need a warrant to ask the cell phone company for location data.
Chatrie
In the lower courts, Chatrie argued that the geofence warrant was insufficient and violated the 4th Amendment. The prosecution argued that it doesn’t actually matter, because the fact that all of that data was with a third party – Google – meant that it was not actually a search at all under the third-party doctrine.
Holding
The U.S. Supreme Court held that a geofence warrant is actually a search, so it does need a warrant. But they did not go further to determine whether the warrant in this case was sufficient, if the process of the search was handled appropriately, or if the data discovered through the warrant could actually be used in the prosecution.
What’s Next?
The case was sent back to continue trying to answer those legal questions now that they have the starting place of knowing that a geofence warrant is a search.
Is Geofence Cell Phone Data Admissible as Evidence?
All of this means that, going forward, we do not have a strong answer on this question yet.
Police must get a warrant if they want to get geofence data, but there is still room to argue that asking for that broad data is simply unreasonable, and that this search is illegal.
We do know that asking for location data for a specific cell phone is legal under Carpenter, but the question of whether they can get blanket data for a whole area is still ultimately unanswered.
Call Our Criminal Defense Lawyers for Help in Pennsylvania
Our lawyers stay aware of the latest legal developments to better defend our clients. For help with your case, call the Allentown, PA criminal defense lawyers at Kenny, Burns & McGill at (215) 774-5644.
