South Carolina officials have released a new video showing the moments before a white police officer shoots an unarmed black man.

The footage taken from a police car’s dashboard camera shows 50-year-old Walter Scott running away after what appears to be a routine traffic infringement.

Michael Slager would eventually pursue Mr Scott and fatally shoot him in the back.

The footage, released by the South Carolina Law Enforcement Division, was taken minutes before a bystander's video recorded Mr Slager gunning down Mr Scott as he fled.

The first video led to Mr Slager's arrest on a murder charge and dismissal from his job.

The shooting was reminiscent of other police killings over the past year in New York, Ferguson, Missouri, and Cleveland, Ohio, rekindling national outrage over excessive use of police force against black men. 

The new video clip, which lasts just four minutes, shows the officer, identified as Mr Slager, approaching a black Mercedes-Benz and asking the driver, Mr Scott, for his licence and proof of insurance.

In an even, professional voice, he tells Mr Scott he was pulled over a broken tail light. 

The two have a brief exchange and the officer returns to his patrol car.

After about two minutes, Mr Scott gets out of the Mercedes car and signals to the officer, who says: “You got to stay in the car”.

Mr Scott gets back into the vehicle and then about 20 seconds later, he emerges again and takes off running.

After the shooting on Saturday, Mr Slager said he fired his weapon because Mr Scott had taken his stun gun and he feared for his life.

The second video offers no evidence of the officer's claim, although there are gaps between the two clips.

Mr Scott does not appear armed at any point in the footage filmed by a bystander, though neither video shows any physical confrontation between the men.

An autopsy found Mr Scott had multiple gunshot wounds on the back of his body.