Brazilian police are responsible for a large number of the 48,000 murders committed in that country each year, the UN Special Rapporteur on extrajudicial, summary, or arbitrary executions said in a report issued late last month. Not only do police routinely resort to deadly violence in the course of their work, they also moonlight as death squad killers for a variety of entities, including drug gangs, said Special Rapporteur Philip Alston.

"In Rio de Janeiro, the police kill three people every day," Alston reported. "They are responsible for one out of five killings," he added in a Monday press statement.

Alston's report came after a fact-finding trip to Brazil last year. While there, Alston met with government officials, including police commanders and senior ministers, as well as non-governmental organizations (NGOs) and over 40 witnesses to human rights abuses.

Brazil's murder rate is among the world's highest, and police vigilantism has played a role for years. Police regularly engage in massive sweeps of poor slum neighborhoods, where drug gangs -- the notorious "commandos" -- often have strong influence or even outright control. Alston was particularly critical of the sweeps, or "mega-operations," which have grown increasingly frequent in Rio de Janeiro.

The report examined one such sweep, a June 2007 operation in Complexo do Alemão. In that sweep, more than 1,450 police attacked the slum, killing 19 people, with independent experts concluding that many of the dead had been executed. But for all the violence, police seized only two machine guns, six pistols, one sub-machine gun, and 300 kilos of drugs.

"Local officials claim that these impressive sounding mega-operations are protecting residents from drug gangs, but the operations have hurt ordinary people far more than they have hurt the drug gangs," Alston said.

The report said there has been little or no outcry over police violence in Brazil because people are skeptical that traditional law enforcement measures are working against the drug gangs. But police death squads have also been implicated in the killings of criminal suspects, the homeless, and even street children, with little outcry.

Police criminality in Brazil extends beyond the job, said Alson. "A remarkable number of police lead double lives. While on duty, they fight the drug gangs, but on their days off, they work as foot soldiers of organized crime," he said. "Clearly, the institutions for holding police accountable are broke, but they are not beyond repair. My hope is that the detailed recommendations in my report will provide a starting point for undertaking the necessary reforms."