Chicago (AFP) - A Chicago police officer pleaded not guilty on Tuesday to murder charges in the shooting death of a black teenager that inflamed tensions over racism and police tactics, court officials said.
Officer Jason Van Dyke's arraignment comes as the midwestern US city is reeling from another fatal police shooting.
Embattled mayor Rahm Emanuel cut his vacation short after police responding to a domestic dispute on Saturday killed a young black man who was allegedly holding a baseball bat as he came down the stairs and also "accidentally" shot dead his neighbour, a mother of five who had answered the door.
Van Dyke, who is white, is the first Chicago police officer to be charged with murder for an on-duty fatality in more than 30 years.
Chicago police initially said Laquan McDonald, 17, was high on the hallucinogen PCP, and had acted erratically and lunged at officers with a knife when he was shot dead in October 2014.
City officials fought for months to prevent the release of a dashcam video which caught his final moments. It showed Van Dyke shooting McDonald 16 times as the teenager walked away.
Prosecutors said Van Dyke opened fire just 30 seconds after his cruiser pulled up to the scene and six seconds after stepping out of it.
Van Dyke was looking forward to clearing his name in court, his lawyer said.
"He wants his story to get out so that people don't see him as this cold-blooded killer, but that's what the trial is for," Dan Herbert told reporters.
McDonald's great uncle said the justice system's culture allows police to "feel comfortable with killing African-American people."
"I believe that the entire criminal justice system in the county of Cook is corrupt," Marvin Hunter told reporters.
"I need someone to prove me wrong by bringing justice in the Jason Van Dyke case."