Paramilitary police personnel on a motorcycle patrol the top of a hill at the Chatuba shantytown, northern Rio de Janeiro, Brazil on 11 september, 2012.. AFP PHOTO / Christophe Simon

A brazilian Army helicopter overflies the Alemao shantytown on March 27, 2012 in Rio de Janeiro, Brazil, during an operation to exchange Army guards for militarized policemen to install progressively Peace Police Units (UPP) to control the slum. AFP PHOTO/ANTONIO SCORZA

Police officers of BOPE and Federal Police carry out an operation against drug trafficking at Morro do Dezoito slum, in Agua Santa, northern Rio de Janeiro, in Brazil, on February 15, 2012. Photo: MARCOS DE PAULA/AGENCIA ESTADO/AE

A Brazilian marines' amphibious assault vehicle (AAV) crushes a motorcycle at a street of Rocinha shantytown in Rio de Janeiro, Brazil, on November 13, 2011. Security forces backed by armor and helicopters peacefully seized control of Rio's largest favela early Sunday in a major assault to expel narcotraffickers who had been ruling the area for 30 years. AFP PHOTO ANTONIO SCORZA

A paramilitary police (PM) helicopter overflies Rocinha shantytown in Rio de Janeiro, Brazil, on November 13, 2011. Security forces backed by armor and helicopters peacefully seized control of Rio's largest favela early Sunday in a major assault to expel narcotraffickers who had been ruling the area for 30 years. AFP PHOTO/LUIZA CASTRO

A police officer helicopter flies over Rocinha slum in Rio de Janeiro, Brazil, Sunday Nov. 13, 2011. Elite police units backed by armored military vehicles and helicopters invaded the largest slum in this seaside Olympic city early Sunday. It's the most ambitious attempt yet to bring security to a town long known for its violence. The action is part of a policing program aiming to drive violent and heavily armed drug gangs out of Rio's slums, where the traffickers have ruled for decades. (AP Photo/Felipe Dana)

Officers from the Military Police's Special Operations Batallian (BOPE) advance through Rio de Janeiro's Morro da Mangueira shantytown early in the morning of June 19, 2011 in a pre-announced operation. Hundreds of Brazilian police and soldiers backed by helicopters and armored vehicles swept in Sunday to take over a crime-ridden Rio slum as part of a pacification plan ahead of the football World Cup in 2014. More than 100 marines and 160 elite police officers took part in the operation in the hillside Mangueira neighborhood, which went off without a shot being fired, a police spokesman said. Drug gangs which had been controlling the district had fled well in advance. AFP PHOTO/VANDERLEI ALMEIDA

A bulldozer of Special Police Operations Battalion (BOPE) removes barricades placed by drug dealers to block the police access, during an operation against trafficking held at the Taquaral slum, in western Sao Paulo, Brazil, on June 3, 2011. Photo: JADSON MARQUES/AE/AE

Officers of the Special Police Operations Battalion (Bope in Portuguese) remove stones from a street blocked by criminals during an operation against trafficking at the Antares and Rola slums, in western Rio de Janeiro, Brazil, on April 20, 2011. Photo: JADSON MARQUES/AE/AE

Police BOPE commandos arrive with an excavator to remove obstacles placed by drug dealers to block the streets at Jacarezinho shantytown in Rio de Janeiro, Brazil, on March 1, 2011. A police operation Tuesday early morning reportedly ended up with five alleged traffickers and one police officer wounded. AFP PHOTO/ANTONIO SCORZA

Police BOPE commandos arrive with an excavator to remove obstacles placed by drug dealers to block the streets at Jacarezinho shantytown in Rio de Janeiro, Brazil, on March 1, 2011. A police operation Tuesday early morning reportedly ended up with five alleged traffickers and one police officer wounded. AFP PHOTO/ANTONIO SCORZA

Police officers of the Special Police Operations Battalion (BOPE) carry out an operation in search for criminals in Jacarezinho slum, in Rio de Janeiro, Brazil, on March 1, 2011. Five people were killed and three others were arrested during the operation. Photo: WILTON JUNIOR/AGENCIA ESTADO/AE

Officers of the Special Operations Battalion and the Federal Police dig in Rio de Janeiro's Ramos beach in search of human remains and weapons following a report that a death squad controlling Roquete Pinto shantytown had been hiding evidence in this site, on February 11, 2011. Some 600 state and federal officers are helping themselves with helicopters and boats in the "Guillotine Operation", to combat corrupt policemen involved with drug traffickers. AFP PHOTO/VANDERLEI ALMEIDA

Officers of the Special Operations Battalion and the Federal Police dig in Rio de Janeiro's Ramos beach in search of human remains and weapons following a report that a death squad controlling Roquete Pinto shantytown had been hiding evidence in this site, on February 11, 2011. Some 600 state and federal officers are helping themselves with helicopters and boats in the "Guillotine Operation", to combat corrupt policemen involved with drug traffickers. AFP PHOTO/VANDERLEI ALMEIDA

Officers of the Special Operations Battalion and the Federal Police dig in Rio de Janeiro's Ramos beach in search of human remains and weapons following a report that a death squad controlling Roquete Pinto shantytown had been hiding evidence in this site, on February 11, 2011. Some 600 state and federal officers are helping themselves with helicopters and boats in the "Guillotine Operation", to combat corrupt policemen involved with drug traffickers. AFP PHOTO/VANDERLEI ALMEIDA

Police officers of Special Police Operations Battalion (BOPE in Portuguese) carry out a search operation for drug gang members at Vila Vintem slum, in Padre Miguel, western Rio de Janeiro, in Brazil, on December 15, 2010. An alleged trafficker was killed. Drugs and guns were seized during clashes with the police. Photo: JADSON MARQUES/AE/AE

Police officers of Special Police Operations Battalion (BOPE in Portuguese) carry out a search operation for drug gang members at Vila Vintem slum, in Padre Miguel, western Rio de Janeiro, in Brazil, on December 15, 2010. An alleged trafficker was killed. Drugs and guns were seized during clashes with the police. Photo: JADSON MARQUES/AE/AE

Police officers of Special Police Operations Battalion (BOPE in Portuguese) carry out a search operation for drug gang members at Vila Vintem slum, in Padre Miguel, western Rio de Janeiro, in Brazil, on December 15, 2010. An alleged trafficker was killed. Drugs and guns were seized during clashes with the police. Photo: JADSON MARQUES/AE/AE

Residents flee the conflict area during the raid in the Morro do Alemao shantytown on November 28, 2010 in Rio de Janeiro, Brazil. After days of preparation, Brazilian security forces early Sunday launched a raid against a slum where between 500 and 600 drug traffickers are holed up and refuse to surrender. About 2,600 airborne troops, marines and members of elite police units were taking part in the operation targeting a lawless group of slums dubbed Complexo de Alemao. The operation has so far killed 35 people AFP PHOTO/Jefferson BERNARDES

Riot Special Forces advance as they invade the Morro do Alemao shantytown on November 28, 2010 in Rio de Janeiro, Brazil. After days of preparation, Brazilian security forces early Sunday launched a raid against a slum where between 500 and 600 drug traffickers are holed up and refuse to surrender. About 2,600 airborne troops, marines and members of elite police units were taking part in the operation targeting a lawless group of slums dubbed Complexo de Alemao. The operation has so far killed 35 people. AFP PHOTO/Jefferson BERNARDES