An inquiry is launched to find out whether Brazilian police used excessive force during the pursuit of a suspected drug dealer.An investigation has been opened into a shoot-out last year in which Brazilian police fired from a helicopter at an accused drug trafficker.They were chasing him through a favela - a shanty town or slum - in Rio de Janeiro.Inquiries into the shooting began after video of the shooting, which took place in May last year, appeared on national television on Sunday.It started after police monitoring one of Rio's most wanted alleged drug traffickers, Marcio "Mathematician" Pereira, told a police helicopter they believed Pereira could be found in the Korea area, in Rio's West zone.The suspect was alleged to be running a drug trafficking ring through four different favelas in one of the most populous regions of Rio.Police reportedly spotted a man who fitted the description of the wanted man and the police helicopter then descended to an altitude from which it could give chase.It was from there that they opened fire, shooting several rounds while chasing the speeding car.The car eventually halted and was surrounded by people in the area.Although Pereira managed to escape, he was found dead in a parked car the next day.Brazilian authorities have now decided to look into the helicopter chase to see if excessive force was used in the pursuit of the suspect.All eyes are on Rio in the run-up to a host of world events beginning with Pope Francis' visit for World Youth Day in July, followed by the 2014 World Cup, and - perhaps the city's biggest test yet - the 2016 Summer Olympics. news.sky.com/story/1087742/rio-police-probe-favela-helicopte , i take no credits for this video or article )