E.g. in Baltimore, we saw the homocide rate spiking as of Freddie Gray protests.

https://epidemiological.net/2017/11/16/a-quick-geographical-...

https://www.copinthehood.com/2017/09/the-freddie-gray-effect...

A particularly good visualization of Baltimore's murder rate is here:

http://mistybeach.com/mark/BaltimoreHomicides.html

Baltimore's homocide clearance rate also dropped from 40% to some percentage in the 20's because the breakdown in police/community relations made people stopped snitching.

There's a similar spike in St. Louis, timed to the Michael Brown killing.

The national murder rate spiked 25% in the last two years of Obama's presidency, after decades of decline. There isn't any alternative explanation.