From the United States Supreme Court
Geofencing to Catch a Bank Robber
Chatrie v. United States, slip opinion No. 25-112
In another case involving technology which was beyond science fiction when the Bill of Rights and specifically the Fourth Amendment was adopted, the United States Supreme Court considered the constitutional implications of law enforcement using geofencing during investigations.
In Chatrie, the Court began with a description of geofencing and its use for investigations and the warrant that was obtained by investigators in this case.
The Court noted that certain apps have the ability to track locations of devices using these apps and therefore can tell law enforcement who, with a device, such as a cell phone was in the vicinity of a crime at a particular time. Thus, law enforcement can establish a virtual perimeter, a geofence, related to a crime, direct a search warrant to the cell service provider, and come up with a list of persons in the area of the crime when the crime occurred.
In this particular case, the investigators were investigating a bank robbery and had some specific information about the movement of the robbery suspect.
The bank robbery occurred in Midlothian, Virginia on May 20, 2019 at approximately 4:50 p.m. The suspect gave the teller a note demanding $100,000 and threatening to harm the teller’s family, noting that he had con-conspirators watching from outside. When the teller said she did not have access to that kind of money, the suspect brandished a firearm and ordered everyone in the bank to the floor. The suspect forced the bank manager to open the safe and left the scene with $195,000.
The Court noted that through investigation, “that the robber had approached the credit union from a corner of an adjacent church, while appearing to talk on a cell phone.” With no other information, the investigators decided to seek a geofence warrant.
The Court described that as geofence warrants developed. Google worked with law enforcement to develop a three-step process for such warrants.
Stage one: Google produces an anonymous list of phone numbers and locations to law enforcement. The information includes the longitude/latitude location of the phone with a timestamp, an estimate of the data’s accuracy, and a description of the source the device is on, i.e. Wi-Fi, cell site, or other. The data shows the location of the phone every two minutes and its movement within the geofence.
Stage two: Investigators whittle down the anonymous list and ask Google to provide further data which usually includes a longer time frame and the device’s location both inside and outside the geofence.
Stage three: Law Enforcement further whittles down the devices and then, through this warrant process, the names, email addresses, and phone numbers of a smaller group of device users, with the whole idea of reaching a small number of suspects to investigate.
The Court noted that several apps, not just Google have received warrants to include, Apple, Lyft, Uber, Snapchat and others.
In this case, at stage one, Google provided 19 users who were within the geofence during the one hour time frame set by the warrant within the time the robbery occurred, including 30 minutes before and 30 minutes after. Law enforcement then whittled down this number and then further anonymous information on devices for a two-hour time frame and movements of the devices both inside outside the geofence.
At the third stage, the investigators narrowed the devices to three and got the identities of the subscribers, which, following some additional investigation, led to Chatrie being charged with the bank robbery.
Throughout his prosecution and appeal, Chatrie argued that the geofence data investigation by law enforcement was a Fourth Amendment search and that the warrant obtained by law enforcement was not valid.
The federal trial court agreed with Chatrie that a Fourth Amendment Search had occurred and that the warrant was invalid, but refused to suppress the location data evidence based on the good-faith exception to the exclusionary rule.
The United States Court of Appeals for the 4th Circuit agreed with the trial court on the admission of the evidence but for a different reason, essentially finding that no search was conducted and therefore law enforcement did not need a warrant. The 4th Circuit asserted that Chatrie had no privacy interest in two hours of location data that he voluntarily exposed to Google.
The Supreme Court noted that it only agreed to hear one aspect of the case, whether the police had violated the Fourth Amendment in obtaining Chatrie’s location data. The Court specifically did not address whether the exclusionary rule should or should not apply.
The Court wrote that the analysis in this case consisted of two parts:
First: Did law enforcement conduct a search when it obtained Chatrie’s location data from Google. On this question, the Court held, that “because an individual has a legitimate expectation of privacy in his cell-phone location data,” a search governed by the Fourth Amendment had taken place.
Second: Did the three-step geofence warrant issued here make the search conducted by law enforcement reasonable and therefore consistent with the Fourth Amendment? The Court did not answer this question but instead, because the 4th Circuit had not addressed this question, sent the case back to the 4th Circuit to decide whether the three-step geofence warrant was sufficient to meet Fourth Amendment standards.
Bottom-Line:
Device location data obtained from a company is a search under the Fourth Amendment and must be done pursuant to a warrant, though maybe a warrant is also insufficient which is the unanswered question sent back to the 4th Circuit.
The unknown: Is the current 3-step warrant process developed with Google sufficient to meet 4th Amendment standards or is it going to take something more to overcome a person’s privacy interest. Note, it could be that because these warrants also gather information on non-suspects, that perhaps only things like national security or life-threatening exigency will justify such warrants.
