A Chicago jury convicted a white police officer of second-degree murder in the 2014 shooting of Laquan McDonald, a 17-year-old African American.

Jason Van Dyke shot McDonald 16 times on the night of October 20, 2014, as the teen, who was carrying a knife, appeared to be walking away from him.

The shooting was captured on police video, sparking outrage throughout the city.

The 12-person jury reached a verdict on Friday, just a day after beginning deliberations. He was also convicted of 16 counts of aggravated battery, and acquitted of one count of official misconduct.

Protesters gathered outside the court as the verdict was read. Video posted on social media, showed activists and others cheering and chanting: “We finally got justice!”

Van Dyke was charged with first-degree murder, a charge that requires a finding that the shooting was unnecessary and unreasonable. The judge told jurors the second-degree charge was also available, requiring them to find Van Dyke believed his life was in danger, but that the belief was unreasonable. Second-degree murder usually carries a sentence of less than 20 years.

Laquan McDonald was shot 16 times by Chicago Police Department Officer Jason Van Dyke in 2014 [File: Paul Beaty/AP Photo]

Van Dyke is the first Chicago police officer to be charged with murder for an on-duty shooting in more than 50 years.

The case has put the city at the centre of the national conversation about police misconduct and excessive force.

Dash-cam video

Video of the shooting, which was released in 2015 through Freedom of Information request, showed that police had McDonald largely surrounded on a city street. According to several officers who testified, they were waiting for someone to arrive with a stun gun to use on the teenager when Van Dyke arrived. The video, played repeatedly at the trial, shows Van Dyke opening firing. McDonald spins, then crumples to the ground. Van Dyke continues to shoot when the 17-year-old is lying in the street.

Prosecutors and defence lawyers argued over what the video actually proved.

Prosecutor Jody Gleason noted during closing arguments that Van Dyke told detectives that McDonald raised the knife, that Van Dyke backpedalled, and that McDonald tried to get up off the ground after being shot. “None of that happened,” she said. “You’ve seen it on video. He made it up.”

Chicago police Officer Jason Van Dyke looks on during his murder trial as a monitor displays a scene from a police vehicle dash cam video, moments after the shooting death of Laquan McDonald [File: John J Kim/Chicago Tribune/Reuters]

But Van Dyke and his lawyers maintained that the video didn’t tell the whole story. His lawyers had portrayed Van Dyke as being “scared’ by the young man who he knew had already punctured a tire of a squad car with the knife. Van Dyke testified that the teen was advancing on him, ignoring his shouted orders to drop the knife. Van Dyke conceded that he did actually step towards McDonald and not away from the teen, as Van Dyke had initially claimed. But the officer maintained the rest of his account, saying: “The video doesn’t show my perspective.”

Van Dyke had been on the force for 13 years when the shooting happened. According to a database that includes reports from 2002 to 2008 and 2011 until 2015, he was the subject of at least 20 citizen complaints – eight of which alleged excessive force. Though he was never disciplined, a jury did once award $350,000 to a man who filed an excessive force lawsuit against him. Van Dyke testified that McDonald was the first person he ever shot.

A week before jury selection, Mayor Rahm Emanuel announced he would not seek a third term, although his office insisted the case had nothing to do with his decision. He had faced criticism that he fought the release of the video until after his re-election in April 2015.

The city’s handling of the case eventually led to the firing of its police chief and a federal investigation into the Chicago Police department.

In advance of the verdict, the city had prepared for the possibility of the kind of massive protests that followed the release of the video in November 2015, with an extra 4,000 officers being put on the streets.

‘Laquan shouldn’t be dead’

Online people celebrated the verdict, but added McDonald shouldn’t be dead in the first place.

“I hate that as Black people we have to be so excited because 1. Laquan shouldn’t be dead [and] 2. We’re so used to no guilty IF it goes to trial,” one Twitter user said.

I hate that as Black people we have to be so excited because

1. Laquan shouldn’t be dead

2. We’re so used to not guilty IF it even goes to trial #LaQuanMcDonald #16shots #VanDykeMurderTrial #Chicago — G. (@_uzunma) October 5, 2018

Others said the second-degree verdict, as opposed to the first, won’t help bring about police reform.

“JUSTICE for the black community would have been Van Dyke receiving a 1st degree verdict with a natural life sentence. This decision is only community appeasement and does nothing to realise police reform. The target is still on BLACK BODIES,” another Twitter user said.

JUSTICE for the black community would have been Van Dyke receiving a 1st degree verdict with a natural life sentence. This decision is only community appeasement and does NOTHING to realize police reform. The target is still on BLACK BODIES. #Justice4LaQuan #VanDykeMurderTrial — Hydroxycholoroking (@conspiracylife) October 5, 2018

we took over the streets of Chicago for #LaquanMcDonald and others whose lives were cut short by state-sanctioned violence. today we find some relief in the

#VanDykeMurderTrial verdict, but the fight continues #16shots pic.twitter.com/ca0oDaIm8F — Prop Joe (@coolstory_joe) October 5, 2018

Nearly 750 police killings in 2018

According to the Washington Post’s Fatal Force database, at least 750 people have been killed by the police in the US this year. The Post found that more than 980 people were killed by police in 2017.

The Guardian identified more than 1,090 police killings the previous year.

Nearly a quarter of those killed by police in 2016 were African Americans, although the group accounted for roughly 12 percent of the total US population.

According to watchdog group The Sentencing Project, African American men are six times more likely to be arrested than white men.

These disparities, particularly the killing of African Americans by police, has prompted the rise of the Black Lives Matter movement, a popular civil rights movement aimed at ending police violence and dismantling structural racism.