“It is difficult to overstate the breadth of this warrant”: The (un)constitutionality of geofence warrants

In United States v. Chatrie, E.D. Va. 19-cr-00130, D.E. 220 (March 3, 2022), the district court found a geofence warrant unconstitutional when it was used to identify a bank robbery suspect. Of course, Leon’s good-faith exception then robbed the suspect of constitutional protection. But still, Chatrie is a rich case with much to offer on geofence technology, Google operations, and the “ongoing efforts to apply the tenets underlying the Fourth Amendment to previously unimaginable investigatory methods.”

What is a geofence warrant? “Google (and others) have begun collecting detailed swaths of location data from their users. Law enforcement has seized upon the opportunity presented by this informational stockpile, crafting ‘geofence’ warrants that seek location data for every user within a particular area over a particular span of time.” A geofence can also be set to alert when a particular device with GPS enters or leaves a defined area. Here, the warrant was used to identify 19 users and then track their location data for a two-hour period.

Is geofence creepily powerful information?  An individual user’s location can be logged up to 720 times in a single day, within three meters and even measures elevation, such as whether the user was on a building’s first or second floor. Once a user opts into Location History (LH), “Google is ‘always collecting’ data and storing all of that data” even “if the person is not doing anything at all with [their] phone.” But Google estimates that LH offers a “68 percent likelihood that a user is somewhere inside” the confidence interval. And “Web and App Activity collects a wider variety of information than Location History.”

Are geofence warrants common? Yes, and increasingly so. While there is little caselaw on the subject (this is why Chatrie is important), in 2019 “Google received around 9,000 total geofence requests.” (The decision differentiates between requests and warrants). Geofence warrants comprise over twenty-five percent of all warrants Goggle receives in the United States. In response, Google established a three-step process for responding to warrants.

Was Google interested in this case? Why, yes, Google really wanted to have a say here, filing an amicus brief and providing testimony that:

  1. Location History is not a business record, but is a journal stored primarily for the user’s benefit and is controlled by the user. (Checkmark for expectation of privacy.)
  2. LH information “can often reveal a user’s location and movements with a much higher degree of precision than [Cell Site Location Information].”
  3. A geofence warrant is certainly a  “search within the meaning of the Fourth Amendment,” because users “have a reasonable expectation of privacy in the LH information, which the government can use to retrospectively reconstruct a person’s movements in granular detail.”

Was this geofence warrant unconstitutional? Yes. The court found:

  1. Google provided the government “an almost unlimited pool from which to seek location data” enabling police to retrace a person’s—or 19 persons’whereabouts.
  2. People other than criminal defendants “have no functional way to assert their own privacy rights.”  
  3. Regarding Google’s three-step plan, “Fourth Amendment protections should not be left in the hands of a private actor.”
  4. A user does not waive constitutional protection by using LH: “a user simply cannot forfeit the protections of the Fourth Amendment for years of precise location information by selecting ‘YES, I’M IN’ at midnight.”
  5. “The geofence warrant fails to establish particularized probable cause to search every google user within the geofence"; and
  6. It would be hard to draft a particularized warrant for this data; but
  7. Leon, because . . . . Leon. 

Has a geofence warrant been considered in the District of Kansas? Yes, considered and rejected and cited in Chatrie. In In the Matter Of The Search Of Information That Is Stored At The Premises Controlled By Google, Llc, 542 F.Supp.3d 1153 (D. Kan.  2021), Magistrate Judge Mitchell rejected a warrant that sought geofence data “from an area surrounding the alleged crime location, which is a sizeable business establishment, during a one-hour period on the relevant date.” We blogged about Judge Mitchell’s order here.

What do ED Virginia and D Kansas have in common? The issuing state magistrate judge was not a lawyer, which is also allowed in Kansas’s state court. But unlike Virginia, which at least requires a bachelor’s degree from an accredited institution, Kansas only requires a high school degree. Chatrie’s magistrate judge’s brief attention to this complicated warrant was considered, as was his qualification to serve as magistrate. This non-lawyer, three years out of college had served only three non-probationary months “before he signed this sweeping and powerfully intrusive Geofence Warrant.” But this did not amount to an exception of Leon.

What else? Aside from just the wealth of technological knowledge and analysis in this decision, it is a good guide for discovery requests, including the communications between law enforcement and Google as they apparently negotiate the terms of the warrant production.

Other reading? Geofence Warrants and the Fourth Amendment, 134 HARV. L. REV. 2508, 2511–12 (2021).

Other value of this decision? Instructions on how to turn off and delete your phone's location history. Maybe take time to do this before writing your motion.