RIO DE JANEIRO (AP) Human Rights Watch said Thursday that a pattern of covering up police killings has thwarted efforts to curb violence in Rio de Janeiro's slums ahead of the Summer Olympic Games in Brazil.
Many of the people killed by police in recent years were unarmed, in custody or trying to flee, according to the 109-page report. Authorities have said that in most cases, the police had come under attack, but prosecutors told the rights group that in the majority of the cases there was no confrontation.
The city is gearing up for the Olympic Games that begin on Aug. 5, with security as one of the main concerns. Rights groups have condemned the increasing use of excessive force in slums and outlying areas. Human Rights Watch said the lack of investigation and prosecution of officers to some extent unraveled a security overhaul that had shown progress.
''You can't be an effective police officer in a community if people distrust you, fear you, they even hate you,'' said Daniel Wilkinson, managing director of the Americas division at the organization. ''It's compromising any effort to improve public security and fulfill this promise for the Olympics.''
Rio police have had a long track record of carrying out extrajudicial killings with more than 8,000 deaths by law enforcement since 2006. However, Wilkinson said police killings dropped from 2007 to 2013 after an effort to reduce crime in violent slums through the use of a new community police force.
But police killings have been rising in the past three years in Rio de Janeiro state, with 645 people killed in officer-involved shootings in 2015, compared to 416 in 2013.
''They failed to deal with this basic problem, which is that there are a lot of cases of police executing people,'' Wilkinson said. ''There's almost zero accountability. These cases aren't investigated, they are not prosecuted and people can get away with them. It was no surprise that after initial progress, the problem of police killings started to bounce back.''
The rate of 3.9 police killings per 100,000 people in 2015 is almost five times that of South Africa's and nearly 10 times that of the U.S.
The New York-based rights group interviewed 34 current and former police officers who detailed a ''culture of combat'' that rewards them for killing instead of arresting drug-trafficking suspects. They said they covered up killings by planting guns on victims, or removing them from crime scenes to deliver dead people at hospitals, destroying evidence in the process.
The organization said it studied 64 cases and found that forensic evidence in half of them was inconsistent with officials' accounts. Autopsies in 20 cases showed the dead had been shot at close range, something not typical of shootouts. The report also showed that Rio police killed five people for each person they injured from 2013 to 2015, a number the group says is ''the opposite of what one would expect.''
The investigative police are usually tasked with investigating police killings, but detectives often do not visit the scenes of the deaths or even interview all of the officers involved, the report said, adding that prosecutors filed charges in only 15 of the 3,441 police killings between 2010 and 2015.
Wilkinson said some recent changes in the justice system bear some promise, such as turning officer-involved killings over to the state's homicide division instead of neighborhood precincts. The group also recommends increasing the number of prosecutors who investigate only police abuse and improving internal investigations within the police.
Rio de Janeiro state security officials did not respond to a request for comment.