Weird, as a UK citizen, I think it's fairly pleasant here and the dystopian nightmare is on the other side of the pond. I can express my beliefs without fear of being jailed or sacked or shot. I wouldn't be in fear of losing my job just because I was black or gay or voted the wrong way. I can walk the streets at night in London and feel perfectly safe, and I certainly don't need a gun to "protect" my home.
Crime does happen here though. It would seem fairly straight forward to see if people with a history of violent crime are associating with people who have a history of abuse. If you then tie that to whether they're having money issues (or drug issues) then it's a simple recipe for potential future problems. That's not to say they should be arrested but it might be worth a social worker visiting and seeing if they need help.
I'll admit in my time that I have known 2 people who committed murder. One guy probably wouldn't of shown up on such a detection system but the other one almost certainly would.
I take it you are politically left leaning. Anyone that post something right off center ends up with the cops on their door step. Half the time, charges are filed. The UK is nowhere near being in a good place. You shouldn't believe the MSM. The US under Trump is about as free as it gets and getting better by the day. He believes in removing criminal Migrants. No Minority report algorithm is going to end well.