NSA surveillance allows for "2hops" in the communication chain of any individual (target) they are allowed to survey. Meaning, if they hit a match on facial recognition while observing a crime and get a warrant they can capture all of his electronic communications, all of the electronic communications of his contacts, and all of the electronic communications of his contact's-contacts. This casts a wide enough net to understand who he is connected to and what his motive was.
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Re: Conservative attacked on UC Berkeley campus
Attacker = member of local ANTIFA chapter (joined April 2018).
Facial scans do not 'hit' directly 2 jumps downstream req.
Q
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'''"facial scans do not hit directly 2 jumps downstream req(fired)."'''
Meaning, facial recognition is not 100% accurate. To assure the perp is who we think he is NSA will verify by tracking his associates within 2 hops.