CHARLESTON, US - A man who recorded chilling video of a white police officer gunning down a black man said Wednesday that the shooting followed a struggle in which the cop had gained control of the situation.
Peaceful protests were held in the evening, with demonstrators saying the quick arrest of the officer averted violent unrest of the kind that erupted in similar cases elsewhere in the US.
The now widely-distributed video of South Carolina officer Michael Slager shooting Walter Scott repeatedly in the back was recorded by 23-year-old Feidin Santana.
The video sparked public outcry and led to a murder charge against the policeman after it challenged the officer's account of the shooting that took place in the coastal city of North Charleston.
The shooting is America's latest high-profile police killing of a black man by white officers.
A string of such shootings of unarmed victims, where officers are rarely charged, have sparked protests around the country with demonstrators alleging racism in the nation's police forces.
"Before I started recording, they were down on the floor. I remember the police (officer) had control of the situation," Santana said in an interview with NBC television about what he witnessed in the moments before filming started.
"He had control of Scott. And Scott was trying just to get away from the Taser (stun gun)."
"I knew right away, I had something on my hands," he said about recording the video.
Slager was arrested and charged with murder after the video surfaced showing him shooting eight times at Scott, 50, while Scott was running away.
He was fired from the police force on Wednesday after being charged with murder and booked into jail.
Slager could face a sentence of up to life in prison or the death penalty.
Mayor Keith Summey announced the sacking at a highly-charged press conference frequently interrupted by residents angered over the killing.
The mayor said the police department would buy body cameras for officers to wear to help investigate shootings.
Dozens of protesters gathered in front of City Hall throughout the day Wednesday and into the night.
Protesters observed a minute of silence while holding candles. One man wore a T-shirt with the slogan 'driving while black is not a crime.'
"Tonight is a mixed emotion. Your heart aches for the family of Walter Scott, your soul is excited for the possibility of having justice," said Bakari Sellers, 30, a black attorney and former member of the South Carolina House of Representatives.
"Things in Charleston would have been worse than things in Ferguson had he not been arrested, if that video hadn't been released," said Michael Brown, 34, a black community organizer in North Charleston.