Video of the incident shows 50-year-old victim running away from South Carolina officer when he was shot.
Protests have been held in South Carolina over the shooting of an unarmed black man by a white policeman, as the mayor of the city where the incident took place announced every officer will be required to wear a body camera.
Up to 50 people rallied at the North Charleston City Hall on Wednesday, protesting over the shooting and killing of Walter Scott after he was stopped over a traffic incident.
The protesters claimed North Charleston police had a habit of harassing black people for small offences, such as the broken brake light that sparked the traffic stop preceding Scott’s death.
Scott, 50, was shot by North Charleston policeman Michael Thomas Slager, who fired eight times in Saturday’s incident.
Slager was charged with murder and has been fired by the police force.
Officials only announced the charge on Tuesday after a graphic video of the incident was released.
The FBI and US Justice Department have also begun a separate investigation.
Scott’s family and their lawyer, L Chris Stewart, called for calm and peaceful protests. They said the murder charge showed that the justice system was working in this case.
Obama requests 50,000 cameras
Their calls for calm came as the the mayor of North Charleston said every officer in uniform on the street will get a body camera.
US president Barack Obama has also requested federal funding to provide body cameras for up to 50,000 officers in America.
North Charleston Mayor Keith Summey said on Wednesday that the city had already ordered 101 body cameras for its officers, and after the shooting, he decided to order 150 more.
It may take some time before the cameras are being used. Summey said officers have to be trained and a policy for the use of the cameras must be written and approved by lawyers.
Saturday’s shooting was captured on video by a bystander, who explained why he recorded the incident on Wednesday.
Feidin Santana told NBC News that he approached the scene as he was walking to work because he noticed Slager controlling Scott on the ground. He began recording when he heard the sound of a taser, a weapon used by police to subdue potential criminals. He said: “Mr Scott was trying just to get away from the taser.”
The video then appears to show Slager firing eight times at the back of the fleeing unarmed man, until he crumples to the ground.
A police incident report says that Slager, who joined the department in 2009, told other officers Scott had taken his stun gun. In the video, Scott does not appear to be armed while running from Slager.
With the victim lying face down on the ground, Slager then appears to approach him and handcuff him. The officer then walks several paces back to where he opened fire, before returning to Scott and appearing to drop an object next to him on the ground.
The shooting was the latest in a series of deaths during police encounters in the United States that have led protesters to decry racism and police brutality.