I caught it half way in so I'm not %100 certain if it was a documentary, docudrama or just a regular film.

The story was about a bunch of kids and teens who lived in a dusty neighborhood in the middle of nowhere with no jobs, no moey, no future. They just stole and robbed and beat each other up. I think some sort of war broke out between the kids/residents and the drug/gun lords and a bunch of people got killed at the end. It wasn't not dubbed, it was in Portuguese, with English subtitles.

Never monkey with another monkey's monkey.