[watwut]

African and South American countries you have in mind have typically highly corrupt police force. Police themselves being often also criminals or cooperating with them is big part of problem. I dont think that is argument for why it is good idea to adopt their tactics.

The murder clearance rates are quite low when I checked, so at least part of issues is the way police prioritize their work. And you wont raise murder clearance rates by surveilling protesters nor by having guns from army nor by arresting people for loitering and what not.

You cant disincentivize homicide when you don't catch murderers. And most murders are also among people who know each other, not random events.