It's not really a needle in haystack problem. If you record every moment of all your citizens. You can build a calendar application where you enter the name of

It's not really a needle in haystack problem. If you record every moment of all your citizens. You can build a calendar application where you enter the name of the person and go through all the moments in question throughout the days of curiosity. Specifically when that person is under suspicions of some criminal involvement. I feel sorry for china because I can only imagine how much more data besides just phone calls are collected from citizens unaware.