Videos of the crashed aircraft emerged on Sunday with reports saying there was shooting in the area prior to the crash.
Police have confirmed the death of four policemen in the crash, Major Ivan Blaz, media coordinator of the Brazilian Military Police told local media, according to Russia Today.
An investigation into the causes of the crash will be carried by Aeronautical Accidents Investigation and Prevention Center, a unit of Brazilian Air Force, on Sunday.
Eyewitnesses on Twitter reported continuous shooting and a police presence in the Cidade de Deus (City of God) neighborhood in western Rio de Janeiro, which is a well-known Brazilian slum area often referred to as CDD.
The helicopter was supporting a police operation in the area when it was brought down. According to the Command of the Pacifying Police Unit (UPP), the altercation began after suspected criminals blocked Edgard Werneck Road, setting fire to tires and waste dumps.
After a police vehicle, which was dispatched to the site to clear off the road, was fired at, members of Brazilian Special Operations Command were called to search for the suspects.
The names of the deceased officers have not been released.