" The lawyer, Caleb Kenyon, dug around and learned that the notice had been prompted by a "geofence warrant," a police surveillance tool that casts a virtual dragnet over crime scenes, sweeping up Google location data — drawn from users' GPS, Bluetooth, Wi-Fi and cellular connections — from everyone nearby. The warrants, which have increased dramatically in the past two years , can help police find potential suspects when they have no leads. They also scoop up data from people who have nothing to do with the crime, often without their knowing ─ which Google itself has described as "a significant incursion on privacy." " https://www.nbcnews.com/news/us-news/google-tracked-his-bike-ride-past-burglarized-home-made-him-n1151761