The Larimer County District Court has quashed a far-reaching search warrant sought by Fort Collins police that would have required Google, LLC to produce a potentially vast trove of data.
Judge Juan G. Villaseñor’s Dec. 6 ruling is the latest in a growing national legal controversy over the use of so-called reverse search warrants, which are used to obtain digital information from technology companies that may help police identify a criminal suspect.
“The [c]ourt has little trouble concluding that the reverse-keyword warrant seeks records that are unusually voluminous in nature and impose an undue burden on Google,” Villaseñor wrote. He was referring to the standard imposed by a federal law known as the Stored Communications Act, which served as the basis for his decision.
A reverse-keyword search “pulls data on everyone who searched a specific set of keywords and, using that date, works backwards to investigative leads or suspects,” according to the National Association of Criminal Defense Lawyers. “Like other reverse search warrants, these do not target someone suspected of being connected to a crime and many unrelated people’s information is caught up in these searches.”
In the case confronting Villaseñor, a Fort Collins detective was investigating an assault that occurred in a local home. The warrant affidavit indicated that police suspected that the perpetrator had cased the house and used Internet search engines, including Google, to look for media coverage of the assault.
The warrant asked Google to produce “anonymized account information and include the IP addresses used by all [Google] accounts” connected with three or more of five separate keyword searches during an 18-day period. The warrant also demanded that Google exclude from the data given to law enforcement “any devices that conducted one or more of the above listed searches using IP addresses located out of the state of Colorado.” The five terms were generic; Villaseñor’s opinion did not specifically list them because doing so “would disclose specific details about the location of the crime and about the victim.”
Google’s counsel argued that the warrant would require it to “execute five searches across a repository containing stored queries that belong to more than one billion monthly users who use Google Search.” Villaseñor agreed with that interpretation of the warrant’s scope, deeming it “the only reasonable way to construe it.”
The veteran jurist, who was appointed to the bench in 2018 after a 15-year career as a prosecutor and assistant U.S. attorney, determined that Google would have to conduct the searches for the keywords in 24-hour increments, which would not necessarily succeed in finding data. “[T]here is a high likelihood that the searches would fail and would need to be restarted, potentially using shorter time frames,” he wrote. And if the 24-hour increment approach worked, Google would be left with “at least 73 separate spreadsheets,” organized according to the five search terms.
Villaseñor also noted the wide reach of the search terms, calling them “breathtakingly broad.” A witness for Google testified that the generic nature of the terms could mean they appear in “millions of searches,” a conclusion the judge found compelling. He then explained that, since each of the 73 or more spreadsheets may end up containing millions of queries, no spreadsheet program available on the retail market would be able to process the data. That, in turn, meant Google would have to create a custom database.
Google’s witness, an analyst on the company’s team that handles and responds to incoming search warrants, told the court that “Google has never performed the reverse-keyword warrant’s requirement to conduct an overlap analysis to determine whether users queried three or more of the search term groups.” She also informed Villaseñor that Google does not have the technical capacity to exclude from the data produced in response to the warrant any IP addresses located outside of Colorado. Villaseñor highlighted those points in his ruling.
The fourth requirement the warrant imposed on Google was to create a list of users that assured the confidentiality of searchers’ identities. This would require company personnel to “go through the custom spreadsheet, assuming it could build one, “row-by row” and then to separately account for each incidence of the matching online search term, the IP address from which each online search originated, and an “anonymized account identifier.”
Villaseñor found that the warrant’s command for data relating to Google searches for the five generic terms “entails an astronomically high number of results, considering that Google users across the globe conduct searches in the range of billions per day.” Therefore, he said, it was an “inexorable conclusion” that the data Google produced would be uncommonly ample.
He also explained that the time it would take Google to comply with the warrant – probably “several weeks” – and the necessity for the company to divert employees, some of whom typically handle other law enforcement warrants, to address the Fort Collins warrant, would be troublesome for Google. Villaseñor also criticized the detective who filed the warrant affidavit for asking the company to analyze the raw data and create the anonymized list of searchers, tasks that “belong[] to law enforcement.”
Legal commentators have, in recent years, expressed concern about the increasing use of reverse search warrants, including an analogue to reverse-keyword warrants known as geo-fence warrants. A geo-fence warrant asks a technology company to search its databases for information about the location of mobile phones within a particular geographic area during a specified period of time.
“In contrast to the typical warrant, these tools reverse the normal assumptions: rather than searching the place or property of a person linked by probable cause to a particular crime, these warrants use broad parameters to identify any person who might have had a potential connection with the evidence,” according to a recent legal academic article. Another essay, published in 2021, argued that reverse search warrants “necessarily involve the very sort of general, exploratory rummaging” that the U.S. Constitution’s Fourth Amendment was intended to bar. This “rummaging and the general awareness that the government may be watching chills associational and expressive freedoms,” it continued.
Google asked Villaseñor to decide whether the reverse-keyword warrant sought by Fort Collins Police violated both the First Amendment and the Fourth Amendment. But he declined to do so because the company could not advocate for the privacy rights of persons who used its search engine. “[I]t’s clear that Google seeks to vicariously assert the Fourth Amendment rights of others, which is verboten,” he wrote. As for the First Amendment claim, the court found that it did not need to consider the issue.
In 2023, the state supreme court bypassed an opportunity to rule on the question whether reverse-keyword search warrants are consistent with the Fourth Amendment and analogous provisions in the Colorado constitution. In a 5-2 ruling that came in a case called Seymour v. Colorado, the justices found that evidence gathered under the authority of such a warrant would be admissible under a doctrine known as the “good faith exception.”
Two federal appeals courts have also addressed the issue of whether reverse search warrants can be squared with privacy protections under the law. A panel of the U.S. 4th Circuit Court of Appeals, based in Baltimore, held last summer that a geo-fence warrant is not considered a “search” at all. That decision is set to be reheard by all of the judges on that court.
Meanwhile, the U.S. 5th Circuit Court of Appeals, which has its home in New Orleans, went the other way. It found in an August decision that geofence warrants can never be consistent with the Fourth Amendment. That court, which is generally considered a conservative bastion in the federal judiciary, proclaimed that “warrants are “emblematic of general warrants and are highly suspect per se,” then went on to warn law enforcement that it “cannot forgive the requirements of the Fourth Amendment in the name of law enforcement.”
Reverse search warrants were unknown before 2016, according to a 2019 story published by The New York Times.
The Fort Collins Police have apparently not filed a criminal case arising from the assault that prompted the reverse-keyword warrant quest. “I know that investigation is ongoing,” said Kylie Massman, a spokesperson for district attorney Gordon McLaughlin. “At this point I don’t believe they have filed another one.”