How Fog Data Science Lets US Police Track Phones Without a Warrant
Since the start of 2026, Nevada state police have gained access to a tool from Fog Data Science that allows real-time tracking of mobile device locations without a court warrant. The technology uses data collected from commercial apps and provides law enforcement with information on the movements of millions of users—even those not suspected of any crimes.
How the Data is Collected: Advertising IDs as the Key
Fog Data Science doesn't interact directly with telecom operators or device owners. Instead, the company aggregates data from third-party sources—primarily mobile apps that send location information to ad brokers. The main identifier in this system is the advertising ID (e.g., IDFA on iOS or AAID on Android). These IDs are assigned to each device by the operating system and are intended for ad personalization.
Although these IDs don't formally contain the user's name, they're tied to a specific device. Over time, behavioral patterns can be reconstructed from them: home and work addresses, travel routes, frequently visited places. Fog Data claims the data is "anonymized," but researchers show that full anonymization is impossible under these conditions—a few location points are enough to identify a person.
Query System: Two Search Modes
The Fog Data platform provides investigators with two types of searches:
- Device Search — enter a specific advertising ID, and the system returns its movement history.
- Geofence Search — specify a geographic area (e.g., a rectangle on a map), and the system lists all devices whose signals were recorded in that zone during the specified period.
A single query can return tens of thousands of records. For example, in investigating a mass incident (explosion, protest, terrorist attack), police can get a list of all devices that were near the scene. These are then cross-referenced with other sources—surveillance cameras, witness statements, social media—to identify individuals.
Legal and Ethical Risks
Traditionally in the US, obtaining cell phone location data requires a warrant based on "probable cause," as required by the Fourth Amendment to the Constitution. However, Fog Data sidesteps this by claiming it sells not "personal data" but "commercial analytics."
Nevada's contract with Fog Data costs $12,000 per year—a sum below the threshold requiring public discussion of the purchase. Funding comes from a federal grant, further reducing transparency. The Nevada Department of Public Safety doesn't disclose which specific crimes are investigated using this technology or how its use is monitored.
Digital privacy experts warn: mass collection of location data without court oversight creates a system of total surveillance. It's especially concerning that data from innocent citizens ends up in the database—just because they installed an app that shares location with third parties.
Practical Use Cases
According to journalistic investigations, Fog Data technology has already been used in other states:
- In murder investigations to identify suspects at the crime scene.
- To track movements of individuals suspected in the January 2021 Capitol riot.
- In analyzing mass gatherings and potential terrorist threats.
In all cases, the system allowed quickly narrowing down persons of interest, but it also invaded the privacy of thousands of uninvolved people.
Key Points
- Fog Data Science collects location data via advertising IDs from commercial apps.
- Nevada police can make up to 250 queries per month without a court warrant.
- The system operates in two modes: by device ID and by geofence.
- Data is formally "anonymized," but easily deanonymized through behavioral patterns.
- A legal loophole allows bypassing US Fourth Amendment requirements.
Developers and users should be aware: installing an app with location access permission can land your device in databases used by law enforcement—even without any suspicion of wrongdoing.
— Editorial Team
No comments yet.