Google is providing law enforcement with a controversial new tool to aid in criminal investigations. Google geofencing is a privacy intrusion on anyone who owns an Android cellphone. Android is now the most popular smartphone operating system. It is important to be aware how Google’s geofencing works because it is in effect everywhere now.
Even if GPS tracking is off on your Android phone, the installed apps, by default, are constantly reporting back your approximate location to Google. This assists in search advertising, restaurant review, shopping, weather, and many other apps that depend on knowing your location in order work. They do so via local cell tower connection data Bluetooth, and wifi access points. Even if you have wifi turned off, Google occasionally turns it on and off. Your location information is stored in a “Sensorvault” maintained by Google, creating a log of where you were and when. Over time the Sensorvault creates a database that tends to show your travel habits.
Police agencies are using geofence data provided by Google to gather information regarding who was present at the scene of a crime. Say there was a murder at a mall. Google would provide the data to the police, who then know what Android cell phones were present at that time. Police analyze that data along with other leads to help determine who may have committed the crime. In Georgia the police do not need a search warrant or court order to get basic geofence information. However, other states have required court orders. Police are not just using this technique to investigate murders. They have used Sensorvault in auto theft cases as well.
The United States Supreme Court observed that detailed travel data like this can provide “an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religious, and sexual associations.” Carpenter v. United States No. 16-402, 585 U.S. ____ (2018)
The Carpenter case ruled that the police must first get a search warrant or court order to obtain a specific named individual’s cellphone location records. However Carpenter is different than the geofence cases because it applies only to police getting a specific suspect’s information. The police need to show probable cause to believe that that that suspect’s cell phone location records constitute evidence of criminal activity. Geofence records on the other hand can lead to personal information about everybody present at a particular place and time.
There is no doubt that the United States and individual state supreme courts will have to rule on at what point will a search warrant be required in order for the police identify everyone present at the scene of a crime.
Here is more information about Google Geofence and Sensorvault.