Today's protest comes amid a turf war involving drug trafficking gangs that has killed at least 10 people in downtown slums in recent days.
The bodies of two young men were discovered late yesterday in the Sao Carlos slum prompting the fiery demonstration near City Hall by about 100 people.
The spasm of violence has taken place in so-called "pacified" slums where police are present, and protesters blame police for some of the recent deaths. The slum pacification program is part of an effort to bring security to the notoriously violent city before the 2016 Olympics.