Supreme Court considers whether police search of cellphone records violates Fourth Amendment
Like many an incautious criminal, Okello Chatrie was nabbed because of his telephone use.
The Virginia armed bank robber wasn’t tracked down based on wiretaps, logs of traditional landline calls, mobile phone contents, or cellular site location information—all of which have been the subject of Fourth Amendment decisions by the U.S. Supreme Court going back nearly a century.
Chatrie was identified as the main perpetrator in a 2019 armed robbery of a federal credit union after police sought a “geofence warrant,” which at the time was a relatively new investigative tool that allowed them to order a reverse search of millions of technology company records to identify people who were in the proximity of a crime.
The warrant was served on Google Inc., which at the time was storing the “location history” information of millions of users who opted in on phones with its Android operating system or through applications, such as Google Maps, on other devices. The geofence warrant results, combined with further detective work, led authorities to Chatrie. He pleaded guilty to the robbery but reserved the right to appeal the denial of his motion to suppress the search.
Next week, the Supreme Court will hear arguments in Chatrie v. United States, which is about whether the execution of the geofence warrant in Chatrie’s case was an unconstitutional search in violation of the Fourth Amendment.
“The cloud did not exist in 1791, but that should not foreclose Fourth Amendment protection” of personal data stored online, Chatrie’s lead lawyer, Adam G. Unikowsky, says in a brief. “Location history readily qualifies as ‘papers’ and ‘effects’ for Fourth Amendment purposes.”
U.S. Solicitor General D. John Sauer, defending the federal prosecution, says in a brief that Chatrie “affirmatively opted to allow Google to collect, store and use location information derived from a cellphone that he employed during his armed robbery,” and the police did not violate his Fourth Amendment rights by seeking data about mobile devices in use near the robbery.
Even as there are questions about the prevalence or effectiveness of geofence warrants, there is wide agreement that the high court’s decision in the case could have implications in other contexts or with the next new search innovation.
The case involves “the intersection of high technology and the Fourth Amendment, or how the Supreme Court applies an 18th-century constitutional guarantee in the face of rapidly advancing technology,” Michael R. Dreeben, a former career deputy U.S. solicitor general who argued several landmark Fourth Amendment cases, said at a recent Georgetown Law Center forum on the case.
Search narrows 500 million accounts to 19, then to 3
It was an afternoon in May 2019 when an armed man entered the Call Federal Credit Union in Midlothian, Virginia, near Richmond, while talking on his cellphone. He handed a threatening note to a teller and brandished a handgun when the employee suggested she did not have access to the “at least 100k” that the note demanded. A manager opened a safe, and the robber escaped with $195,000 in cash.
The police investigation had hit a dead end in mid-June when a detective decided, based on security footage showing the robber using his phone, to seek a geofence warrant directed at Google. The application sought information about devices within 150 meters of the credit union for a half hour before and after the robbery.
A state magistrate signed the warrant subject to a three-step process that Google itself had developed to narrow the frequent requests from with law enforcement that the company considered to be overly broad.
At step one, Google searches its location history records to come up with an anonymous list of users who meet the time and location criteria. In the credit union robbery, this led to an initial list of 19 relevant phone accounts. At step two, investigators narrow the list to accounts most likely relevant to the crime. After that step whittled the list to nine accounts, investigators requested and received, as part of step three, a list of three most relevant phone accounts, now including names and email addresses. One of those belonged to Chatrie.
Further investigation led police to discover that Chatrie had recently purchased a gun of the type used in the robbery. Authorities obtained separate federal warrants to search Chatrie’s home, where they found robbery-demand notes and nearly $100,000 in U.S. currency in bands tying the bills to the credit union.
Chatrie was arrested, and he confessed and pleaded guilty to robbery of a credit union and brandishing a firearm in a crime of violence. He was sentenced to nearly 12 years in prison. The Richmond, Virginia-based 4th U.S. Circuit Court of Appeals last year denied the appeal of his motion to suppress in a 14-1 en banc decision in which some judges agreed there was a Fourth Amendment violation but one that could be excused based on a good-faith exception.
Questions on whether broad canvas of data is a search
Chatrie’s lawyers argue that geofence warrants are an unconstitutional form of “general warrant” that most concerned the drafters of the Fourth Amendment.
“The Fourth Amendment was born of the founders’ revulsion for general warrants and writs of assistance—instruments that allowed the government to search first and develop suspicions later,” Unikowsky wrote in a brief.
Laura Donohue, a professor of law and national security at Georgetown, said at the April 8 forum that it wasn’t just 19 accounts subjected to search under the geofence warrant, but “500 million people [who] had their telephone records searched to see if they were present in the geofence location. … Google performed this search at the behest of the government, and the government kind of has the audacity to argue, ‘We didn’t do it, Google did it.’”
Indeed, the U.S. solicitor general argues that Chatrie lacks a Fourth Amendment interest in the information Google provided to law enforcement because he enabled location history. That made the information different, Sauer said, from the seven days of cellphone site location information at issue in Carpenter v. United States, a 2018 case decision in which the Supreme Court held that the government needed a warrant to gather that information.
“Unlike CSLI, which every user must share to make a cellphone functional, Google’s location history here was an optional add-on,” Sauer says in a brief.
Orin S. Kerr, a Stanford Law School professor and leading scholar of the Fourth Amendment, is also on the government’s side. But he believes geofence warrants are largely a practice “no longer in place.”
He notes that Google changed its policies in 2023 and now stores location history not on its own servers but on individuals’ devices, which clearly require particularized warrants to search. His amicus brief cites an email exchange he had with a former top Google security official who said that successful geofence warrant investigations “were very uncommon.”
Still, Kerr says, “there are a lot of issues at stake” in the case. One is whether searches of large-scale databases run by Google or other large tech companies are even a search, and whether the police can obtain warrants for them.
“All the digital user records are stored by these huge providers,” Kerr says. “If they can’t be searched, even with a warrant, that would be a dramatic holding with far-reaching implications.”
Implications for keyword searches and other contexts
Google acknowledges in its own amicus brief, filed in support of neither party, that its decision to move location storage from servers to individuals’ devices means “Google can no longer respond to geofence warrants based on location history data.”
It has moved to quash many geofence warrant requests, the brief says.
“Americans do not have to forgo technological innovation in order to retain their basic constitutional rights,” the company says.
A group of law professors supporting Chatrie argues in an amicus brief that a decision upholding the geofence warrant “could unleash a much broader wave of similar reverse searches, and to identify pools of private information that investigators are likely to want to fish in next.”
These could include reverse keyword searches, such as the police asking who researched a potential victim’s name, or sweeping searches of video surveillance images using human-identity recognition.
“There are lots of other types of data and information that might be equally attractive to law enforcement,” says Megan Graham, a law professor at the University of Iowa and the director of its Technology Law Clinic.
“The Fourth Amendment is deeply rooted in the idea that general searches were anathema to constitutional freedoms and protections,” she says. “The founders were really trying to prevent the government from being able to root around in people’s homes and papers and lives without some quantum of suspicion or probable cause. The question in front of the court right now is, what does that conception look like in a digital era that is as complicated and fast-changing as it is today?”
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