Here's a security video of a robbery at a Brazilian pizza takeout shop. It gets very bloody when police arrive on the scene. WARNING: When I say 'very bloody' I mean it! You're going to see people die. Not for the squeamish!
(I wish the person who put this on YouTube had left out the daft music soundtrack. The video would have been far more effective in silence, IMHO. I recommend you mute your speakers.)
I guess the moral of the story is, don't mess with Brazilian cops. They mean business, and they don't seem to bother with warnings.