By Bryce Yancey



Since 2018, a company called Fog Data Science has been procuring and selling private individuals’ data which allows private security companies and government agencies to track people without a warrant through its program called ‘Fog Reveal.’[1] Fog Reveal uses its technology to take cellphone location data that was originally collected by smartphone apps.[2] Each cell phone has an advertising ID that is comprised of a set numbers that are unique to the specific phone.[3] Fog Reveal uses smartphones’ GPS capability, which provides detailed location data that it collects from commercially available data brokers that wherever a smartphone goes and any time a user downloads an app or visits a website, a trail is created.[4]

This has become especially controversial since several of the Company’s clients include several government entities, including Virginia State Police.[5] Police have been able to use the technology to sweep an area to see which phones were in a particular location at a given time.[6] The technology has been used in several criminal investigations, including the murder of a nurse in Arkansas in 2018 and tracing participants from the January 6, 2021, attack on the capital.[7] However, the technology is rarely, if ever, mentioned in court documents.[8]

Fog Data Science has maintained that the data collected is anonymous and isn’t tied to individuals.[9] However, the true nature of Fog Reveal came to light when a digital privacy nonprofit called ‘Electronic Frontier Foundation’ publicized information through the Freedom of Information Act that found the data collected was indeed linked to individuals.[10] A senior attorney for Electronic Frontier Foundation said it’s “child’s play” for police to figure out the identity of any given cellphone user based on their individual patterns of life, including where they live, sleep, and work.[11]

The U.S. Supreme Court has ruled in Carpenter v. United States that the Constitution’s Fourth Amendment protects individuals from unreasonable search and seizures by requiring law enforcement agencies to obtain a warrant before tracking someone using a GPS device or cell site location information.[12] However, Fog Reveal technology has been used as a loophole to get around these requirements and to gather the same information without court oversight or public transparency. This technology usage has brought to light to many the differences between Electronic surveillance and data privacy. Under the Electronic Communications Privacy Act and Fourth Amendment of the Constitution, law enforcement officers are required to get a warrant based on probable cause if they wish to intercept communications or track a person’s location.[13] However, the concern raised by many is that there aren’t any comprehensive laws that protect people from their data being bought and sold to government agencies and private entities.

However, there is hope. Civil Rights lawyers and Senators have started pushing for legislation limiting law enforcement’s ability to purchase peoples’ data without a warrant.[14] But until any meaningful steps are taken, data capturing will continue to expand in both the public and private sectors as the unregulated data market grows.




[1] Jason Dearen & Garance Burke, Senators push to reform police’s cellphone tracking tools, ABC 13 News (September 29, 2022),

[2] Ben Paviour, Virginia State Police is using software to track cellphone location data, VPM News (January 12, 2023, 12:54 AM),

[3] Anne McKenna, What is Fog Reveal? A legal scholar explains the app some police forces are using to track people without a warrant, The Conversation (October 17, 2022, 8:31 AM),

[4] Garance Burke & Jason Dearen, Tech tool offers police ‘mass surveillance on a budget,’ AP (September 2, 2022),

[5] Paviour, supra note 2.

[6] Id.

[7] Dearen & Burke, supra note 1.

[8] Id.

[9] Paviour, supra note 2.

[10] McKenna, supra note 3.

[11] Paviour, supra note 2.

[12] Carpenter v. United States, 138 S. Ct. 2206 (2018).

[13] Electronic Communications Privacy Act of 1986, 18 U.S.C. §§ 2510-2523.

[14] Dearen & Burke, supra note 1.


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