I can weigh in a bit on what the police claim happened here in Indianapolis. They won't account for all of their CS deployments, which I think is crazy, but they did address why it started the other day (Saturday?). Their claim is that what they saw was some police inside the city/county building and a single person started hitting the glass on the building. Simultaneously, "previously peaceful" protesters started locking arms at one end of the street, blocking emergency vehicle ingress, so they let loose a bunch of (13 year expired)_CS gas.

Is that believable? Sure, but locking arms is also a common thing during protests. The road was already blocked off and cars weren't going through. Also, they fired CS into crowds of protesters blocks away, claiming that they think the protesters are coordinating by secure communications and instantaneously turning violent across the city. Most of it seems like bullshit, and even if it's all true, locking arms on one side of a closed street is not at all unusual. They should have arrested the one guy hitting the glass and let the protest continue.

By the way, they used this event to justify the curfews that haven't been raised since then.