In the 33 years I’ve spent pounding the pavement and working surveillance from the front seat of my Ford Explorer, I’ve seen the “toolkit” of an investigator change more than a few times. We went from paper maps and film cameras to GPS trackers and cellular forensics. But there is a new shadow looming over the investigative world—one that doesn’t involve binoculars or telephoto lenses, but rather the very digital footprints we all leave behind.
The legal world is currently bracing for a seismic shift. This week, the U.S. Supreme Court heard oral arguments for Chatrie v. United States, a case that could rewrite the rules of digital privacy and the Fourth Amendment for decades to come. As someone who lives and breathes evidence, I can tell you: this isn’t just a “police case.” It’s a turning point for how we define privacy in the 21st century.
To understand the stakes, you have to understand the tech. In my line of work, if I want to know where someone is, I usually have to follow them or get a court order for a specific GPS tracker on a specific vehicle.
A Geofence Warrant—often called a “reverse warrant”—works in the opposite direction. Instead of starting with a suspect and finding their location, law enforcement starts with a location and finds everyone who was there.
Imagine a virtual “fence” drawn around a crime scene—say, a bank that was robbed at 10:00 AM. The police serve a warrant to a tech giant like Google, asking for the location data of every single device that entered that circle during a specific window of time.
The Dragnet: Google searches its “Location History” (formerly stored in a massive database known as Sensorvault) for every user whose phone “pinged” inside that fence.
Anonymized Data: Initially, the police get a list of “anonymous” ID numbers and coordinates. They look for patterns—who stayed too long, who moved toward the getaway route?
The Unmasking: Once they pick out a “suspicious” ID, they go back to the court to get the actual name, email, and identity of that user.
The man at the center of this, Okello Chatrie, was identified as a suspect in a 2019 Virginia bank robbery using exactly this method. The “fence” the police used didn’t just cover the bank; it covered a church and surrounding areas, sweeping up the data of hundreds of people who had nothing to do with the crime.
Chatrie’s lawyers are arguing that this is a “General Warrant”—the exact kind of “fishing expedition” the Founding Fathers tried to ban with the Fourth Amendment. Traditionally, the Fourth Amendment requires particularity: you need probable cause for a specific person or place. With geofencing, you’re searching thousands of innocent people to find one needle in the haystack.
From where I sit, this is a double-edged sword.
On one hand, geofencing is a miracle for cold cases. If a crime happens in a remote area with no witnesses, the “digital witness” of a smartphone is a game-changer. It’s a tool that can close cases that would have stayed open forever in the 90s.
On the other hand, the privacy implications are staggering. Most people don’t realize that by having “Location History” turned on for their maps or weather apps, they are effectively wearing a government-accessible ankle monitor. During the Supreme Court arguments yesterday, several justices expressed skepticism. Justice Sotomayor pointed out that location data follows you everywhere—into your home, your doctor’s office, and your house of worship.
“If the Fourth Amendment is to hold any force in the future,” as one legal brief put it, the Court has to decide if “opting-in” to a tech service means you’ve signed away your constitutional right to be left alone.
If the Supreme Court rules in favor of Chatrie, it could effectively kill the geofence warrant as we know it. Police would be forced to return to “traditional” investigative work: witness interviews, physical surveillance, and forensic evidence.
If they rule for the government, it opens the floodgates. We could see geofencing used not just for bank robberies, but for protests, political gatherings, or even minor traffic infractions. As an investigator, I know that once a surveillance tool becomes “easy,” it becomes the default.
Interestingly, the tech companies are already jumping ship. Google recently updated its systems so that Location History is stored on your individual device rather than their central servers. This makes it much harder for them to comply with these “bulk” warrants because they technically don’t “have” the data in a central pile anymore.
In the PI business, we often say that “information is the only currency that matters.” But there’s a cost to that currency.
As we wait for the Supreme Court’s decision this summer, we are at a crossroads. We have to decide if we’re okay with the police having a “time machine” that can look back at any street corner and see who was standing there.
Whether you’re a private citizen or a detective like me, your “digital trail” is more visible than ever. My advice? Check your privacy settings today. Because while the Supreme Court is still debating the law, the technology isn’t waiting for a verdict.
Stay safe, and keep your eyes open.
— Investigator Ranno
Lead Investigator, Ranno Investigative Services
