A police officer questions a youth at Santa Marta slum in Rio de Janeiro, Brazil, June 11, 2015. A shootout last month, the first gun battle in seven years between Rio de Janeiro police and drug traffickers in Santa Marta, has raised concerns a police campaign - for which Santa Marta, with its reputation as a peaceful slum with stunning views, was the model - is running out of steam a year before half a million visitors arrive for the 2016 Olympics. No one was injured in the maze of alleys and steps of the "favela" that is home to 6,000 people, but the incident, in the wake of the stabbing deaths of a cyclist and a German tourist, has sparked fears that after years of progress, violence is on the rise again in Brazil's postcard city. Picture taken June 11, 2015. To match Feature OLYMPICS-RIO/VIOLENCE REUTERS/Pilar Olivares 

Boys play soccer as a policeman patrols one day after the occupation of the Mare slums complex in Rio de Janeiro, March 31, 2014. The federal troops and police occupied the Mare slums complex on Sunday to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW SPORT SOCCER WORLD CUP SOCIETY) 

Police officers patrol at Santa Marta slum in Rio de Janeiro, Brazil, June 11, 2015. A shootout last month, the first gun battle in seven years between Rio de Janeiro police and drug traffickers in Santa Marta, has raised concerns a police campaign - for which Santa Marta, with its reputation as a peaceful slum with stunning views, was the model - is running out of steam a year before half a million visitors arrive for the 2016 Olympics. No one was injured in the maze of alleys and steps of the "favela" that is home to 6,000 people, but the incident, in the wake of the stabbing deaths of a cyclist and a German tourist, has sparked fears that after years of progress, violence is on the rise again in Brazil's postcard city. Picture taken June 11, 2015. To match Feature OLYMPICS-RIO/VIOLENCE REUTERS/Pilar Olivares 

Police officers patrol at Santa Marta slum in Rio de Janeiro, Brazil, June 18, 2015. A shootout last month, the first gun battle in seven years between Rio de Janeiro police and drug traffickers in Santa Marta, has raised concerns a police campaign - for which Santa Marta, with its reputation as a peaceful slum with stunning views, was the model - is running out of steam a year before half a million visitors arrive for the 2016 Olympics. No one was injured in the maze of alleys and steps of the "favela" that is home to 6,000 people, but the incident, in the wake of the stabbing deaths of a cyclist and a German tourist, has sparked fears that after years of progress, violence is on the rise again in Brazil's postcard city. Picture taken June 18, 2015. To match Feature OLYMPICS-RIO/VIOLENCE REUTERS/Pilar Olivares 

Police officers patrol at Santa Marta slum in Rio de Janeiro, Brazil, June 18, 2015. A shootout last month, the first gun battle in seven years between Rio de Janeiro police and drug traffickers in Santa Marta, has raised concerns a police campaign - for which Santa Marta, with its reputation as a peaceful slum with stunning views, was the model - is running out of steam a year before half a million visitors arrive for the 2016 Olympics. No one was injured in the maze of alleys and steps of the "favela" that is home to 6,000 people, but the incident, in the wake of the stabbing deaths of a cyclist and a German tourist, has sparked fears that after years of progress, violence is on the rise again in Brazil's postcard city. Picture taken June 18, 2015. To match Feature OLYMPICS-RIO/VIOLENCE REUTERS/Pilar Olivares 

A man takes a shower as policemen patrol during an operation at the Mare slums complex in Rio de Janeiro, March 30, 2014. Federal troops and police occupied the Mare slums complex on Sunday to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW SOCIETY SPORT SOCCER) 

Police helicopters fly over the Mare slums complex in Rio de Janeiro March 30, 2014.The federal troops and police occupied the Mare slums complex on Sunday to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Sergio Moraes (BRAZIL - Tags: CRIME LAW SPORT SOCCER) 

A woman extends a sheet on a clothesline as police officer patrols during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW) 

A police officer takes up position during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW) 

A child inside a car looks at partially demolished houses next to the construction work for the Rio 2016 Olympic Park in the Vila Autodromo favela in Rio de Janeiro, Brazil, June 9, 2015. Residents have been threatened with eviction and required to move due to the construction work for the Rio 2016 Olympic Park, and about half have so far accepted compensation offers and left. The land conflict in Vila Autodromo, which feels like a ghost town with 90 percent of its residents gone, shows the underside of Rio's attempt to use the 2016 Olympic Games to modernize the city. REUTERS/Pilar Olivares 

Residents observe as policemen take up position near an area where two men were found dead on top of the Sao Carlos slums complex in Rio de Janeiro May 15, 2015. According to residents of the complex, there is an ongoing war between drug dealers in the region and these two men were killed by the police during a police operation in the same area the previous night. Police told local media that they will investigate the deaths. REUTERS/Ricardo Moraes

A policeman runs to take position near an area where two men were found dead on top of the Sao Carlos slums complex in Rio de Janeiro May 15, 2015. According to residents of the complex, there is an ongoing war between drug dealers in the region and these two men were killed by the police during a police operation in the same area the previous night. Police told local media that they will investigate the deaths. REUTERS/Ricardo Moraes 

A Brazilian Army soldier patrols the Mare slums complex in Rio de Janeiro, April 5, 2014. The federal troops have taken control of security operations in Mare slums complex to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW MILITARY SOCIETY SPORT SOCCER WORLD CUP TPX IMAGES OF THE DAY) 

Girls rest along an alley as police officers patrol during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW) 

A police officer from the Pacifying Police Unit (UPP) patrols the streets of the Cantagalo slum in Rio de Janeiro March 13, 2014. After a half-century of neglect, it seemed the government finally cared about Rio's notorious slums, or favelas, with the implementation of an effort to reclaim huge swaths of the city from criminals. This was done through police occupations of historically violent neighbourhoods. Five years into the program, police now occupy 37 major favelas, home to 1.5 million people. Picture taken March 13, 2014. To match Insight BRAZIL-SLUMS/ REUTERS/Pilar Olivares (BRAZIL - Tags: POLITICS CIVIL UNREST SOCIETY POVERTY) 

A resident looks on as a Brazilian Army soldier patrols the Mare slums complex in Rio de Janeiro, April 5, 2014. The federal troops have taken control of security operations in Mare slums complex to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW MILITARY SOCIETY SPORT SOCCER WORLD CUP) 

A police officer takes up position during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW) 

A policeman takes up position during an operation at the Mare slums complex in Rio de Janeiro March 30, 2014. The Federal troops and police occupied the Mare slums complex on Sunday to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW SOCIETY) 

A Brazilian Army soldier patrols the Mare slums complex in Rio de Janeiro, April 5, 2014. The federal troops have taken control of security operations in Mare slums complex to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW MILITARY SOCIETY SPORT SOCCER WORLD CUP) 

A police officer takes up position during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday. Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW TPX IMAGES OF THE DAY) 

Residents react as policemen take position during an operation in the Mare slums complex in Rio de Janeiro March 26, 2014. Brazil will deploy federal troops to Rio de Janeiro to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said on Friday.
Less than three months before Rio welcomes tens of thousands of foreign soccer fans for the World Cup, the attacks cast new doubts on government efforts to expel gangs from slums using a strong police presence. The city will host the Olympics in 2016. REUTERS/Ricardo Moraes (BRAZIL - Tags: CRIME LAW TPX IMAGES OF THE DAY)