Imagine drawing a box on a map and declaring that every person who was within that area during a given time is a suspect in a crime. That is the effect of a surveillance tool called a geofence warrant.
In practice, a geofence warrant allows law enforcement agencies – federal, state and local – to require big tech companies, like Google, to disclose every electronic device within a given area at a given time.
Similarly, a keyword warrant requires a company to disclose the identities of every person who searched a specific keyword.
In effect, geofence and keyword warrants allow government agents to go on massive fishing expeditions.
They claim this investigative tactic helps break cases open. But in fact, it unwittingly sweeps hundreds or even thousands of innocent people into a single criminal investigation. These individuals suddenly find themselves in government crosshairs merely for the simple act of walking or driving through a given location at a given time.
The Electronic Frontier Foundation (EFF) says these broadly constructed warrants “have serious implications.”
“Their increasingly common use means that anyone whose commute takes them by the scene of a crime might suddenly become vulnerable to suspicion, surveillance, and harassment by police. It means that an idle Google search for an address that corresponds to the scene of a robbery could make you a suspect.”
For instance, police collected the location data of people in the vicinity of a police shooting protest in Kenosha, Wisconsin, in August 2020. According to the EFF, the ATF used geofence warrants to identify people as far as a football field away from the protest area.
EFF called it a “surveillance dragnet.”
Geofence warrants also run afoul of the Fourth Amendment because they require no probable cause. As the EFF noted, “The only ‘evidence’ supporting a geofence warrant is that a crime occurred in a particular area, and the perpetrator likely carried a cell phone that shared location data with Google.”
Geofence warrants are eerily similar to general warrants issued by the British in colonial America. Writs of Assistance allowed government agents to enter private homes and businesses to search for evidence of smuggling. Much like geofence and keyword warrants, general warrants did not specify the place to be searched, nor limit what these government agents could search for.
According to the New York Times, federal agents first utilized geofence warrants in 2016.
In theory, these broadly construed warrants help law enforcement pinpoint possible suspects and witnesses in the absence of other clues. Google employees told the Times the company often responds to a single warrant with location information on dozens or hundreds of devices.
A massive Google database known as “Sensorvault” holds detailed location records of at least “hundreds of millions of devices worldwide” dating back nearly a decade, according to Google employees interviewed by the New York Times. One employee said the company has received as many as 180 requests for location information in a single week. In 2021, Google reported that geofence warrants made up a quarter of all law enforcement demands.
According to the ACLU, the use of geofence warrants is growing exponentially. The number of reverse location warrants Google received from the federal government grew by 1,171 percent between 2018 and 2020, while the number of reverse location warrants issued to Google by state and local law enforcement grew by 813 percent in California, 901 percent in Florida, 1,291 percent in Michigan, 1,867 percent in Missouri, and 5,333 percent in Massachusetts during that same time.
There is even a company to assist law enforcement agencies in drawing up geofence warrants that comply with court opinions on the subject.
North Carolina produced the first public reports of this investigative tactic in 2018 after detectives obtained warrants to obtain location data for all the phones that were in the area of two shootings.
According to WRAL news in Raleigh, “On a satellite image, they drew shapes around the crime scenes, marking the coordinates on the map. Then they convinced a Wake County judge they had enough probable cause to order Google to hand over account identifiers on every single cell phone that crossed the digital cordon during certain times.”
Police did not demand information on specific suspects. As WRAL put it, investigators got information about “any mobile devices that veered too close to the scene of a crime.”
In many cases, geofence warrants come with gag orders. According to WRAL, “These warrants often prevent the technology giant for months from disclosing information about the searches not just to potential suspects, but to any users swept up in the search.”
And of course, this kind of data is imprecise. The New York Times opened its report on geofence warrants with the story of an Arizona man whom police arrested in a murder investigation based on location data and other circumstantial evidence. He spent a week in jail before investigators realized they had the wrong guy.
Once collected, this data is almost certainly shared with other law enforcement agencies.
Federal, state, and local law enforcement agencies can share and tap into vast amounts of information gathered at the state and local level through fusion centers and a system known as the “information sharing environment” or ISE.
In other words, surveillance like this on a local level will also create the potential for the federal government to track the movement of millions of Americans with no warrant, no probable cause, and without the people even knowing it.
Fusion centers were sold as a tool to combat terrorism, but that is not how they are being used. The ACLU pointed to a bipartisan congressional report to demonstrate the true nature of government fusion centers:
“They haven’t contributed anything meaningful to counterterrorism efforts. Instead, they have largely served as police surveillance and information sharing nodes for law enforcement efforts targeting the frequent subjects of police attention: Black and brown people, immigrants, dissidents, and the poor.”
Fusion centers operate within the broader ISE. According to its website, the ISE “provides analysts, operators, and investigators with information needed to enhance national security. These analysts, operators, and investigators…have mission needs to collaborate and share information with each other and with private sector partners and our foreign allies.”
In other words, ISE serves as a conduit for the sharing of information gathered with or without a warrant. Known ISE partners include the Office of Director of National Intelligence which oversees 17 federal agencies and organizations, including the NSA. ISE utilizes these partnerships to collect and share data on the millions of unwitting people they track.
While there are currently no public records revealing how geofence data is shared, automatic license plate reader data sharing provides a warning. Records obtained by the Electronic Frontier Foundation (EFF) revealed that law enforcement agencies that collect ALPR data share it with a minimum of 160 other agencies. In some cases, agencies share this data with as many as 800 other agencies.
PUSHBACK FROM BIG TECH
Geofence warrants are so intrusive that even big tech companies including Google, Microsoft, and Yahoo would like to see them ended. These companies signed on to a public statement in support of a New York bill to ban geofence and reverse keyword searches.
Meanwhile, in December 2023, Google announced three changes to the way it handles location history that could make it impossible for it to provide any useful information with geofence warrants.
- Location data will be stored on a user’s device by default instead of in the cloud.
- Location data will automatically be deleted after three months. Currently, data is stored for at least 18 months and often longer.
- If users back up their data in the cloud, Google will “automatically encrypt your backed-up data so no one can read it, including Google.”
EFF said it is “cautiously optimistic” that these changes will effectively stop geofence warrants. With these policy changes, Google won’t likely have access to data requested in a geofence warrant.
“The repository of everyone’s location data dating back months or years was a hazard, and Google is trying to clean up that hazard,” ACLU attorney Jennifer Granick told Forbes. “That is a real benefit for people’s privacy for people’s locations over time which is some of the most revealing information about us.”
But EFF warns that Google stores location information in other places.
“It remains to be seen whether law enforcement will find a way to access these other stores of location data on a mass basis in the future.”
And while Google is the primary source of geofence data, they aren’t the only one. According to Forbes associate editor Thomas Brewster, AT&T, T-Mobile, and UScellular have also provided data requested through a geofence warrant.
The most effective way to stop geofence and keyword warrants is to ban them at the state level. And, more importantly, for people to learn how to restrict location sharing on their devices as much as possible.
