The US Supreme Court appears to be divided over the controversial use of “geofencing” search warrants.

The U.S. Supreme Court on Monday heard arguments in a landmark legal case that could redefine the digital privacy rights of people across the United States.

The case, Chatri v. United States, centers on the government’s controversial use of so-called “geofencing” search warrants. Law enforcement and federal agents use these warrants to force technology companies, like Google, to hand over information about which of its billions of users have been in a particular place and time based on the location of their phones.

By casting a wide net over a technology company’s stores of users’ location data, investigators can reverse engineer who was at a crime scene, effectively allowing police to identify criminal suspects similar to finding a needle in a digital haystack.

But civil liberties advocates have long argued that geofencing orders are inherently broad and unconstitutional because they return information about people who are nearby but have no connection to an alleged incident. In several cases over recent years, geolocation warrants have ensnared innocent people who were nearby by chance and whose personal information was requested anyway, been improperly filed to collect data outside their intended scope, and been used to identify individuals who attended protests or other lawful assemblies.

The use of geofencing warrants has seen a rise in popularity among law enforcement circles over the past decade, with a New York Times investigation finding that the practice was first used by federal agents in 2016. Every year since 2018, federal agencies and police departments across the United States have served thousands of geofencing warrants, accounting for a large percentage of the legal demands received by technology companies like Google, which stores massive amounts of location data collected from user searches, maps, and Android devices.

Chatri It is the first major Fourth Amendment case heard by the U.S. Supreme Court this decade. The decision can decide whether geofencing orders are legal or not. Much of the case rests on whether people in the United States have a “reasonable expectation” of privacy regarding information collected by the tech giants, such as location data.

It’s not yet clear how the nine Supreme Court justices will vote — a decision is expected later this year — or whether the court will explicitly order a halt to the controversial practice. But arguments heard before the court on Monday give a sense of how the justices might rule on the issue.

“Inspection first, then raising suspicions later.”

The case focuses on Okello Shatri, a Virginia man who was convicted of robbing a bank in 2019. Police at the time saw a suspect in the bank security footage talking on a cellphone. Investigators then served a “geofencing” search warrant to Google, demanding that the company provide information about all phones that were located within a short radius of the bank and within an hour of the robbery.

In practice, law enforcement can draw a shape on a map around a crime scene or other place of interest, and ask to scan large amounts of location data from Google databases to determine who was there at a given time.

In response to the geofencing order, Google provided sets of anonymized location data belonging to its account holders who were in the area at the time of the robbery, and investigators then requested more information about some accounts that had been close to the bank for several hours before the job.

Police subsequently received the names and associated information of three account holders – one of whom was identified as Chatri.

Chatri eventually pleaded guilty and was sentenced to more than 11 years in prison. But as his case progressed through the courts, his legal team said evidence obtained through the geolocation warrant, which allegedly linked him to the crime scene, should not have been used.

A key point in the Chatri case invokes an argument that privacy advocates have often used to justify the unconstitutionality of geofencing orders.

They say the geofencing warrant “allowed the government to search first and raise suspicions later,” adding that it contravenes well-established principles of the Fourth Amendment, which sets up guardrails to protect against unreasonable searches and seizures, including of people’s data.

As the Supreme Court watchdog site SCOTUSblog points out, a lower court agreed that the geofence warrant did not establish the “probable cause” prerequisite linking Chatri to the bank robbery, which justified the geofence order to begin with.

The argument was made that the memo was too general because it did not describe the specific account containing the data investigators were looking for.

But the court allowed the evidence to be used in the case against Chatri anyway because it determined that law enforcement acted in good faith in obtaining the arrest warrant.

According to a blog post by civil liberties attorney Jennifer Stessa Granik, a friend-of-the-court brief presented to the court by a coalition of security researchers and technologists provided the “most interesting and important” argument to help guide its final decision. The brief argues that this geofencing warrant in the Chatri case was unconstitutional because it ordered Google to actively sift through data stored in the individual accounts of hundreds of millions of Google users to get the information police were looking for, a practice that conflicts with the Fourth Amendment.

However, the government largely claimed that Chatri “affirmatively chose to allow Google to collect, store and use” his location data and that the memo “simply directed Google to locate and deliver the necessary information.” The US Attorney General, Dr. John Sawyer, who defended the government ahead of Monday’s hearing, said: “Chatri’s arguments seem to imply that no injunction of any kind can be enforced.”

After a split in the Court of Appeal. Chatri’s lawyers asked the US Supreme Court to take up the case to determine whether the geofencing orders are constitutional.

The justices seemed mixed after hearing the arguments

Although this case is unlikely to affect Shatri’s sentence, the Supreme Court’s ruling could have broader implications for Americans’ privacy.

After live-streamed oral arguments between Chatri’s lawyers and the US government in Washington on Monday, the court’s nine justices appeared largely divided on whether to explicitly ban the use of geolocation warrants, though the justices may find a way to narrow the scope of how search warrants can be used.

Oren Kerr, a law professor at the University of California, Berkeley, whose expertise includes Fourth Amendment law, said in a lengthy social media post that the court would “likely reject” Chatri’s arguments about the legality of the arrest warrant, and would likely allow law enforcement to continue using geofence warrants, as long as they are limited in scope.

Cathy Gillis, an attorney who writes for Techdirt, said in a post that the court “seems to like geofencing orders but may be reluctant to get rid of them entirely.” Gillis’s analysis predicted that there would be “small steps, not big rules” in the court’s final decision.

Although the case focuses largely on searching Google’s location databases, the implications reach far beyond Google but for any company that collects and stores location data. Google eventually moved to storing its users’ location data on their devices rather than on its servers where law enforcement could request it. As a result, the company stopped responding to geolocation authorization requests last year, according to the New York Times.

The same cannot be said about other technology companies that store their customers’ location data on their servers, within the reach of law enforcement. Geolocation notes have been introduced for Microsoft, Yahoo, Uber, Snap, and others in the past.