Traditionally, search warrants only went one direction. A crime was committed or suspected, and the police would investigate. Witnesses would be contacted. A theory would be developed. When the police had probable cause to search for evidence, they got a search warrant and searched.
Since smart phones began tracking people’s locations, however, police have been engaging in an interesting new tactic. Instead of searching for witnesses of a crime, they head straight over to a tech firm that has tracking data. Typically using a court order, they demand that the company pull up a list of all the phones that were in the area at a specific time and date. Then, they cull through those phones to find a suspect.
Instead of tracking one person’s location over time, they can now track many people’s locations at a specific moment. Instead of getting a warrant for one person, they can get a warrant for the data of multiple people. This is called a “reverse search warrant.”
For example, in late 2018, the leader of a far-right group known as the Proud Boys was scheduled to speak in Manhattan. A group known as Antifa was planning to protest. When they did, members of the Proud Boys responded with violence. The police used a reverse search warrant to find everyone whose phone had been in the area on that date.
Somewhat alarmingly, the plan wasn’t to identify members of the Proud Boys, but of Antifa, whose protests had been nonviolent. That illustrates one of the concerns people have about the use of this tactic. Reverse search warrants can provide a tremendous amount of data about people who were not involved in any crime. That data can be used to prosecute actual criminal activity or merely to persecute unpopular groups.
The Proud Boys/Antifa incident was only one of several that have taken place over the past couple of years. Both state and federal law enforcement have used reverse search warrants to obtain data from Google, Apple, Uber, Lyft and even Snapchat. In one case, the ATF compelled Google to hand over info on 1,500 cellphones simply because they had all been in an area of 29,387 square meters.
Devices and apps that track you can be used by the government
One problem with reverse search warrants is that they potentially turn our phones and apps into surveillance devices for the government. Moreover, the judges who approve them probably don’t realize just how much data they can secure or how many people the warrant may affect.
Reverse search warrants are like a digital dragnet. They bring in the “likely suspects” but also many innocent people. Courts need to be wary of these tactics.