Met Theresa Williamson, founder and president of Catalytic Communities, an organisation that works to destigmatise favelas and their residents.  She says the problem in violence currently seen in the favelas is as much a problem with so-called militia groups, as it is with traditional drugs trafficking factions.  Both provide supoosed security in favela communities.  Militias dole out severe punishment, including decapitation, for those who disobey their particular rules.
According to Theresa, 41% of favelas are currently under the control of militia groups, while another 41% are under the control of drugs gangs.
Theresa defined a favela as a community that is exempt from state services, not to be confused with a squat, a shanty, or a slum, she says.
She says favelas are the safest places in Rio de Janeiro.  Petty crime does not exist at all within the favela community, and residents leave their doors open all of the time.  Those living in the community know better than to go thieving, etc. as that may call in the attention of police, which is completely unacceptable to whoever is ruling the roost.
Blog posted December 2011, refers to interview conducted November 2011