Chicago white cop charged with murder of black teen

A Chicago police officer was charged with first-degree murder in the 2014 shooting death of a 17-year-old African-American, prosecutors said.

Police officer Jason Van Dyke allegedly shot Laquan McDonald 16 times, continuing fire after the teenager fell to the ground, and stopped only after another police officer intervened during the October 2014 incident, reports dpa.

The incident was among a series of high-profile shootings of young black men by white police officers in recent years that have sparked protests across the country, including riots last year in Ferguson, Missouri, and in April in Baltimore.

Video released late Tuesday by Chicago authorities shows McDonald walking down the middle of a wide street at night with something glinting in his hand.

He walks past - not toward - several police at a distance of several metres when one officer opens fire. McDonald appears immediately hit and spins, before his body stiffens and he falls to the pavement.

By late Tuesday, crowds had gathered in downtown Chicago, but there were no immediate reports of violence.

Cook Country State's Attorney Anita Alvarez had taken more than a year to investigate the incident before filing the murder charge, but said she moved to file charges ahead of the video's release.

Van Dyke turned himself in and was being held without bail, the Chicago Tribune newspaper reported.

The police union had said Van Dyke acted in fear of his life after McDonald lunged at him with a knife, and that McDonald had drugs in his system at the time of his death.