You can read about one such case, one that created enough social repercussion that the cops involved had legal trouble, here:
https://recordtv.r7.com/fala-brasil/videos/mpsp-ira-indiciar...
Most often nothing happens.
https://recordtv.r7.com/fala-brasil/videos/mpsp-ira-indiciar...
Most often nothing happens.
My comment, and my personal experiences, relate to America. At least here, I don't know of any events where police have opened fire on a pack of teenagers partying without reason. But they could exist, which was why I was asking for evidence.