Troubling footage has emerged of a drugs operation in which police fired machine guns from a helicopter into a densely-populated neighbourhood.
The force in Rio was trying to kill the leader of a drugs gang last year. People living in the shanty town say it is a miracle that no innocent civilians were killed or injured.
And ITV News has spoken to one senior policeman who said the footage made him ashamed.
Our Brazil Correspondent Nick Ravenscroft reports:
In the past year more than 500 people have died as a result of police operations in the city.
One of the residents told ITV News described the recent machine gun attack on the street was like something out an action film.
There are more than 700 shanty towns or 'favelas' in Rio, home to nearly a quarter of the population of the city.
Marcelo Freixo, from Brazil's Human Rights Commission, said police tactics are putting many innocent civilians at risk.
Speaking to ITV News, he said:
Rio police said they are still investigating the incident.