WASHINGTON, United States (AFP) — A former US police officer has been indicted on federal charges over the fatal shooting of a black motorist in South Carolina last year, one of a series of incidents that sparked protests over perceived racist abuses by law enforcement personnel.

A grand jury on Tuesday formally charged Michael Slager with deprivation of rights under colour of law, use of a weapon during the commission of a violent crime, and obstruction of justice.

He faces up to life in prison for the civil rights violation and a $US250,000 fine if convicted.

Slager was dismissed from the North Charleston police force and charged with murder, after shooting Walter Scott.

Scott was shot in the back five times as he tried to run away from Slager on April 4, 2015, after being pulled over, reportedly for a broken brake light.

Slager “shot Walter Scott without legal justification, wilfully depriving him of the right, secured and protected by the Constitution of the United States, to be free from the use of unreasonable force by a law enforcement officer,” read the indictment filed in US District Court in Charleston.

The weapon was a .45 calibre Glock pistol.

According to the indictment, Slager “knowingly misled… investigators by falsely stating that he fired his weapon at Scott while Scott was coming forward at him with a Taser.”

“In truth and in fact, as defendant Michael Slager then well knew, he repeatedly fired his weapon at Scott when Scott was running away from him.”

Slager, 34, was arrested and charged with murder three days after video of the incident emerged. He fired his weapon eight times, hitting Scott five times.

His trial for murder is scheduled to begin October 31.

After the federal counts were announced, Scott’s mother, Judy, said the charges were an answer to her prayers.

“This is a sad day for me. But I thank God that the prayers of the righteous availeth much,” she said, paraphrasing the

Bible. “God knew from the beginning what went on.”

Judy Scott said she hopes Slager’s prosecution will also help end a pattern of police malfeasance.

“They tried to cover it up again, but it’s time that the cover was pulled. I thank God that my son was the one that was used to pull the cover.”

The death of Scott, who was 50, set off protests in the city and followed a string of highly publicised incidents of deadly police violence against African Americans around the country.