Magistrate Grants Search Warrant for Google Geo-Fencing Data in Chicago Arson Investigation

Today a magistrate judge in the United States District Court for the Northern District of Illinois granted a search warrant application to investigators from the Chicago Fire Department looking into a string of arsons. The search warrant grants investigators access to Google’s electronic geo-fencing data.

The case is interesting on a number of accounts, ranging from the application of the Fourth Amendment (drafted in the 1780s) to high-tech digital information in 2020; to the potential for this technology to assist in many other types of investigations. Here are some of the highlights from the decision by Magistrate Sunil R. Harjani:

• In this case, the government seeks geofence data in connection with an arson investigation.
• When a Google user opts in to a service known as “Location History,” that user can keep track of locations visited while in possession of the mobile device.
• Like a journal or log, Google Location History Information enables a user to record where she has traveled with her phone and when, and the Google User has the ability to review or delete Location History information at will.  
• If the Google user takes additional steps, including enabling a “Location Reporting” feature for at least one mobile device, the resulting data is transmitted to Google for processing and storage on Google’s servers.
• When activated in such a way, Google can calculate the device’s estimated latitude and longitude using inputs from (1) nearby cell sites, (2) GPS signals, and (3) signals from nearby Wi-Fi networks and Bluetooth devices.
• Google records the margin of error for its calculation as to the location of a device as a meter radius, referred to by Google as a “map’s display radius,” for each latitude and longitude point.
• Google also retains subscriber information associated with a user’s account, which can include the subscriber’s full name, address, telephone number, and other identifiers.
• Thus, a “geofence warrant” provides the government the ability to obtain location data for a Google user for a particular area and, eventually, subscriber information for the account holder using Google-based devices or applications in that area.
• In 2019, there was a series of approximately 10 arsons in the Chicago area, which appeared to target specific commercial lots.
• In most of the arsons, incendiary fires burned vehicles in the lots.
• As further discussed below, various surveillance and investigative techniques led law enforcement to believe that the fires were connected and that geofence data for six “target locations,” will contain evidence pertaining to the identity of the arson suspects and their co-conspirators.
• The government’s warrant contemplates that Google will disclose its geofence data in two steps.
• In the first step, Google will provide the government with anonymized lists of devices with corresponding device IDs, timestamps, location coordinates, margins of error, and data sources for the devices that Google calculates were or could have been within each target location during the time periods described.
• In the second step, the government, at its discretion, will identify to Google the devices from the anonymized lists for which the government seeks the Google account identifier and subscriber information.
• Google will then disclose to the government that information.
• The issue presented here concerns the scope of law enforcement’s ability to seize geofence location data from Google in its search for criminal suspects under the Fourth Amendment’s search and seizure clause.
• Courts have expressed concern about requests for geofence data that sweep too broadly and capture vast amounts of location data on uninvolved individuals.
• For example, geofence zones can be drawn, at the government’s discretion, to include large swaths of land and buildings, including office and apartment buildings, shopping malls, churches, and residential neighborhoods, which could result in revealing location data of hundreds, if not thousands, of individuals that are uninvolved in the underlying crime.
• This is because the nature of a geofence warrant does not target an individual, but rather an area that captures location data for cell phones within that area.
• As a result, it is easy for a geofence warrant, if cast too broadly, to cross the threshold into unconstitutionality because of a lack of probable cause and particularity, and overbreadth concerns under Fourth Amendment jurisprudence.
• The Fourth Amendment protects “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,” except “upon probable cause.”
• Put simply, probable cause is a fair probability that contraband or evidence of a crime will be found in a particular place, based on the totality of the circumstances.
• Here, there is ample probable cause that the crimes of arson and conspiracy to commit arson have occurred.
• There is also probable cause that evidence of the crime will be located at Google because location data on cell phones at the scene of the arson, as well as the surrounding streets, can provide evidence on the identity of the perpetrators and witnesses to the crime.
• Once the location data is produced and reviewed, the government can obtain subscriber information on those cell phones, which will reveal the identifiers of the potential culprits and witnesses to the events.
• For the reasons stated above, the Court finds that the government’s proposed search warrant satisfies the requirements of the Fourth Amendment, and thus the Court grants the government’s application for the warrant