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Scientists Use WiFi to See Through People's Walls
(www.popularmechanics.com)
This is a most excellent place for technology news and articles.
Actually, police do tend to be reasonably ahead when technology is invasive. I've heard many stories about them seeing through walls with other technology. They also tend to like face-tracking, which is pretty advanced. They just are really far behind on technology that could be used to hold them accountable.