SAN FRANCISCO–Millions of Americans’ everyday movements can be traced by police with the click of a mouse and possibly without a warrant, thanks to a data broker that’s selling phone geolocation data to state and local law enforcement, an Electronic Frontier Foundation investigation has found. 

The investigation, conducted by a team of EFF experts led by Staff Technologist Bennett Cyphers, found Virginia-based Fog Data Science sells a service that it bills as allowing police to see where a person was at any point in time over the past several years. This surveillance not only includes possible crime scenes, but also homes, churches, workplaces, health clinics, or anywhere else.

The data is collected and passed through a chain of businesses before ending up with law enforcement.  First, personal location data is gathered via thousands of common apps that people use on Android and iOS phones, that people install for various purposes and may not suspect are gathering and sharing that information further. It is then bought by data brokers that resell it to others, including Fog Data Science, which in turn sells it to cops. While other data brokers sell geolocation data to large federal law enforcement agencies, Fog markets itself to the hometown cops with whom most Americans are far more likely to interact.

“This data could be used to search for and identify everyone who visited a Planned Parenthood on a specific day, or everyone who attended a protest against police violence,” Cyphers said. “Fog already has extensively traced innocent people’s movements just to close its sales pitches, and local police have cast wide nets for minor crimes. The potential for abuse is staggering, and from what we’ve found so far, there are few or no rules protecting our constitutional rights.”

In marketing materials sent to state highway patrols, local police departments, and county sheriffs across the nation, Fog Data Science claims to have “billions” of data points about “over 250 million” devices, and that its data can be used to learn where targets work, live, and associate–in police lingo, a "pattern of life." Agencies can buy in for less than $10,000 per year.

State police in Maryland, Indiana, and New Jersey, the highway patrols in California and Missouri, and the Tennessee Bureau of Investigation have had contracts with Fog lasting at least one year. Police in New York City, Houston, and the Broward County, FL Sheriff’s Office bought access to Fog’s service, as did much smaller agencies including the police in Lawrence, KS (population 97,000) and the sheriff of Washington County, OH (population 60,000).

EFF learned about Fog after filing more than 100 public records requests over several months for documents pertaining to government relationships with location data brokers. Records received by EFF indicate that Fog has past or current contracts with at least 18 local, state, and federal law enforcement clients, while other agencies accepted free trials. 

Troublingly, records show Fog and some police agencies didn’t believe this surveillance implicated people’s Fourth Amendment rights and so they didn’t obtain a warrant before searching through people’s location data. And glaringly absent from the public records EFF received were any documents establishing policies or other limits about when and how police could and should deploy this massive digital dragnet.

Among the findings: In Chino, CA, police used Fog’s service to do massive sweeps determining who was near minor theft and burglary scenes. In a rural Missouri murder investigation, Fog’s service tracked a babysitter who was never a suspect. In Greensboro, NC, a crime analysis supervisor raised red flags about its constitutionality, and later quit after his warnings were ignored. 

EFF shared these documents with the Associated Press, which published its report Thursday: Tech tool offers police 'mass surveillance on a budget'

EFF has published its own series of articles as well:

For more on Location Data Brokers: