A new type of warrant is allowing law enforcement officers to obtain from Google the locations of all cell phones in a given area during a given time window, providing location information on possibly thousands of private citizens as well as perpetrators of crimes.

Police departments in Minnesota have been granted at least 22 “reverse location” warrants since August 2018, part of a growing trend among police departments throughout the country as investigators attempt to tap into new technology to solve crimes quickly and more effectively. However, concerns are being raised by civil rights groups like the American Civil Liberties Union that the scope for those warrants is too broad and jeopardizes the privacy of innocent civilians.

“I am concerned about the breadth of these warrants,” Teresa Nelson, legal director at the ACLU of Minnesota, said. “When you look at the warrant clause in the Fourth Amendment, it talks about the requirement that you not only have probable cause, but that you also state with particularity the place to be searched or the person or things to be seized. I’m concerned that these don’t have the required particularity.”

However, the police department in Eden Prairie, MN, stands by their collection of “digital evidence” while refusing to go into the specifics of any investigation.

“Digital evidence is often stored on personal devices and/or on remote servers owned by the thousands of companies that manage the millions of applications that collect data,” Eden Prairie Police said in a statement. “In specific cases, gathering digital evidence may include executing search warrants for location data possessed by Google or any one of the many other companies that store location data.”

The process used by Eden Prairie and other departments is a two-warrant process. The first warrant casts a wide net by specifying a time window and general location and pulling in the position of all cellphones that were in the area at the time, using Google's location services. A second warrant targets an individual or a tighter group to get specific identifying information about their accounts.

Information obtained by the first warrant is anonymous, simply identifying that there was a phone at that location without any identifying factors like device or phone number, but there is no requirement that the information be purged after the investigation is over. In fact, the data becomes public record in accordance with freedom-to-information legislation and could be accessed by anyone under those laws.

Minnesota has a “tracking warrant” law that requires law enforcement to apply for specific warrants with specific requirements before attempting to gather GPS or tracking data. However, in any Minnesota case that is referred to federal courts, investigators can circumvent those stricter limitations, which is what has allowed reverse location warrants in the state to proceed, Nelson said.

“You do have to have some sort of identification of what you’re looking for,” Nelson said. “These warrants, even though they’re anonymized, they’re scooping up large, vast amounts of data. One warrant … included an intersection that is very heavily traveled. If you’re talking about getting every device that has gone through that intersection over a period of two days, you are scooping up vast amounts of innocent people’s information. That’s problematic as well.”

During the debate over William Barr’s confirmation as attorney general, both Democrats and Republicans raised concerns about his willingness to push for government surveillance. During his earlier tenure as AG in 1992, he ordered the mass collection of phone data by the Drug Enforcement Agency, which helped set the foundation for powers the government would later broaden with the PATRIOT Act in the early 2000s.

The U.S. Supreme Court addressed this issue in 2018 when it ordered that cellphone data could only be collected by the government with a warrant. It was widely assumed that the 5-4 decision would apply to digital data as well.

“Here the progress of science has afforded law enforcement a powerful new tool to carry out its important responsibilities,” Justice Roberts wrote in the decision. “At the same time, this tool risks Government encroachment of the sort the Framers, ‘after consulting the lessons of history,’ drafted the Fourth Amendment to prevent.”

Justice Roberts went on to say that just because the data was gathered by a third party doesn’t mean it isn’t protected by the Fourth Amendment, which guarantees citizens protection from unreasonable searches and seizures.