The company Dataminr tries to scan all posted tweets to find anything suggestive of possible violent intent, and report it to the thugs.

Contrary to its name, the company doesn't seem to do this by data mining. Instead it hires a lot of people to make off-the-cuff judgments, which naturally reflect racist presuppositions and generate biased results. (I call this phenomenon BIBO, for "Bias In, Bias Out.")

Identifying "gang members" by questionable criteria has a long and horrible history in California prisons.