Image copyright
AFP
A Chicago jury has reached a verdict in the murder trial of a white police officer who killed an unarmed black teenager in 2014.
Jason Van Dyke shot Laquan McDonald 16 times, seconds after arriving on scene, claiming he feared for his life as the 17-year-old was armed with a knife.
The jury is expected to deliver its verdict within the hour.
The shooting sparked a nationwide outcry. Chicago is preparing for protests.
Mr Van Dyke was charged with first-degree murder in 2015 after dashcam footage appeared to show him fatally shooting Mr McDonald as he moved away from officers, contradicting official accounts. He pleaded not guilty.
A judge ordered police to release the dashcam footage in November 2015 after Chicago Mayor Rahm Emanuel's administration fought to withhold the video for a year.
The long-delayed footage resulted in mass protests, culminating with the dismissal of the police chief and a Department of Justice investigation into the Chicago Police Department's use of force and practices.
Three other Chicago officers were charged last year with allegedly conspiring to cover up the fatal shooting, and they will be tried later this year.
According to prosecutors, Mr McDonald was holding a knife with a 3in (7.6cm) blade when he was stopped by police on 20 October 2014. Police said he had slashed a tyre on a patrol car, resulting in a stand-off between the teenager and officers.
Mr Van Dyke was not among the first officers to arrive - the policeman who was on scene first told prosecutors he saw no need to use force with Mr McDonald.
Prosecutors say Mr Van Dyke proceeded to open fire on Mr McDonald less than six seconds after he exited his patrol car, and he was the only officer who used his weapon.
Mr McDonald still had a pulse when paramedics arrived, but was declared dead at the hospital.
In the wake of the shooting, police superintendent Garry McCarthy was ousted and the county's top prosecutor, Anita Alvarez, lost her re-election bid amid harsh criticism over her investigation of the incident.