"Lawmaker questions Google's CEO about geofence warrants"

From CNet, via NACDL's News-of-Interest:

Geofence warrants are facing legal challenges across the US, and on Wednesday, a member of Congress questioned Google about the increasingly-popular police surveillance method. 

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Unlike a normal search warrant, geofence warrants don't need a specific person or probable cause to get data from Google. It's essentially a search in reverse, where police send a warrant to Google for a time and a place, demanding that the company provides information on all devices that were in that region during the specified time.