Violent protests broke out in Rio's landmark beachfront district of Copacabana last night, following the death of a resident less than two months before Brazil hosts the World Cup.
Two main thoroughfares were closed after angry demonstrators from a slum set ablaze barricades of tyres to protest the death of a dancer.
Brazilian media quoted police sources as saying Douglas Rafael da Silva Pereira, 25, had been killed after being mistaken for a drug trafficker.
Friends of the dead man alleged he was beaten to death after attempting to take refuge in a school in the community.
A Police Pacification Unit was set up in the area in December 2009 as part of efforts to smash organised crime ahead of June's World Cup.
"The circumstances surrounding the death of Douglas are under investigation. An on-site report indicates Douglas's injuries are compatible with a death caused by a fall," police said in a short statement.
"Witnesses and residents will be called upon to give evidence" as investigations continue.
Police have been cranking up efforts in recent months to clear favelas, which they say are controlled by criminals, before the month-long World Cup kicks off on 12 June.