CHICAGO – A jury on Friday found Chicago Police Officer Jason Van Dyke guilty of second-degree murder in the 2014 shooting death of 17-year-old Laquan McDonald.

The October 2014 shooting was one in a series of deadly confrontations between law enforcement and black men and women that spurred a national conversation on policing and an incident that fractured the already tattered trust of police in the African-American community of the nation’s third-largest city.

A forlorn Van Dyke stared straight ahead as the verdict was read.

He was found guilty of a single count of second-degree murder in McDonald's death and 16 counts of aggravated battery – one for each shot he fired at the teen. The jury found him not guilty of official misconduct.

Cook County Circuit Judge Vincent Gaughan revoked Van Dyke's bond and ordered him taken into custody.

A sentencing date was not set. Second-degree murder carries a sentence of from four to 20 years. Aggravated battery carries a sentence of from six to 30 years.

Van Dyke had been charged with first-degree murder. Gaughan told jurors this week they could consider a second-degree murder charge.

Van Dyke's lead attorney warned that the guilty verdict would have a chilling effect on police everywhere.

“Police officers are going to become security guards,” attorney Daniel Herbert said.

Special Prosecutor Joseph McMahon said he hoped the verdict would mark a turning point in relations between black residents and law enforcement.

“Laquan McDonald was not a throwaway young man,” McMahon said. “He should have been arrested that night, and that’s where the story should have ended.”

The Rev. Marvin Hunter, McDonald’s great-uncle, called the verdict "a victory for America." But Hunter said he felt varying emotions as the verdict was read.

“When I looked over and I saw (Van Dyke’s) wife, my mind had to go to his daughters, his wife – who didn’t pull the trigger – his daughters who didn’t pull the trigger, his father – who may have put all of the evil in him that could possibly be put in him, didn’t pull the trigger,” Hunter said. “I could see the pain in those people, and it was touching my heart to see their pain. But it was also bothering me that they couldn’t see the pain that was within us.”

Dozens of activists and residents celebrated outside Cook County’s Leighton Criminal Courthouse. Demonstrators later took to the streets of downtown Chicago, briefly tying up traffic in the city's upscale shopping district on Michigan Avenue known as the Magnificent Mile.

The shooting on the southwest side of Chicago was captured on police dashcam video – graphic footage that appeared to show McDonald turning away from police when Van Dyke opened fire.

Police were called to the scene after reports of a person breaking into vehicles on a truck lot. They found McDonald wielding a knife with a 3-inch blade.

The troubled teen ignored repeated calls from police to drop the knife. He popped the tire of a police vehicle and scratched a windshield.

Van Dyke arrived on the scene, got out of his vehicle and fired 16 shots at McDonald. He continued to shoot at McDonald for 12.5 seconds after he was already on the ground.

Van Dyke told investigators that McDonald raised the knife in a menacing manner before he fired and that he backpedaled as the teen approached. The police video did not support the officer’s account.

"None of that happened!” prosecutor Jody Gleason told jurors. “You’ve seen the videos. He made it up to justify his use of force."

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Van Dyke's lawyers stressed that McDonald had a long history of violent behavior and drug use and was behaving erratically in the moments and hours before the shooting. The teen suffered from mental illness.

A pharmacologist who testified on behalf of the defense said the PCP in McDonald’s system and the absence of psychotropic drugs the teen was prescribed were a volatile combination. Juvenile detention center officers recalled violent and profane outbursts from the teen while he was in custody. Officer Leticia Velez, who was present at the scene, testified that McDonald looked “deranged.”

Herbert, Van Dyke’s lead attorney, told the jury the shooting was a "tragedy but not a murder."

"Laquan McDonald was the author, choreographer of this story,” he said.

Police encountered McDonald after receiving calls that a young man fitting the teen’s description had been breaking into vehicles and stealing radios from a truck lot on the city’s southwest side.

The trucker who initially confronted McDonald, Rudy Barillas, testified that McDonald attacked him. But Barillas also said that he was able to fend off the teen by throwing his mobile phone and pebbles at him.

Prosecutors noted that there were at least 10 other officers at the scene, but Van Dyke was the only one to shoot. They used testimony from Laurence Miller, a forensic psychologist who evaluated Van Dyke in 2016 at the behest of the defense team, to bolster their case that the officer acted with malice.

Van Dyke and his partner had just stopped for coffee at a nearby 7-Eleven when they heard radio calls and sped toward the scene.

As Van Dyke and partner Joe Walsh drove toward McDonald, Miller said, Van Dyke asked Walsh why the officers on the scene hadn't shot McDonald since he attacked.

During the psychological evaluation, Miller said, Van Dyke recalled remarking to Walsh: “Oh my God, we’re going to have to shoot the guy.”

Van Dyke testified this week in his own defense.

McDonald's "face had no expression, his eyes were just bugging out of his head," Van Dyke said. "He had these huge white eyes just staring right through me.”

He said he believed his fellow officers “were under attack”

“The whole thing was shocking to me,” he said.

The only black juror to hear the case told reporters Friday that the officer hurt himself with his testimony.

“He messed up,” said the woman, who spoke to reporters on the condition her name not be published. “His testimony wasn’t credible to me. I felt that he was trying to remember stuff that he said that maybe wasn’t true.”

The initial resistance of local leaders to release the video fueled allegations by activists that Mayor Rahm Emanuel and the police department were trying to cover up wrongdoing.

A court eventually ordered the city to release the footage, 400 days after the shooting. On the day of its release, Van Dyke was charged with first-degree murder.

The county prosecutor, Anita Alvarez, accused by activists of taking too long to charge the officer, was voted out of office. And local and federal authorities launched investigations of the police department.

Emanuel saw his standing in the city's sizable African-American community plummet. He fired his police superintendent, and announced last month that he wouldn’t seek a third term in office.

He insists the Van Dyke trial did not affect his decision.

The police department’s relationship in the African-American community had been strained by a long history of police brutality and allegations of heavy-handed tactics in the city’s low-income and minority communities.

The city borrowed some $709 million to pay settlements in police misconduct cases from 2010 to 2017, according to the Action Center on Race & the Economy.

A U.S. Department of Justice review last year found Chicago officers used force nearly 10 times more often in incidents involving black suspects than against white suspects.

Antonio Romanucci, a Chicago attorney who has alleged misconduct by the Chicago Police Department in several civil lawsuits, said the prosecution's case centered on making clear to the jury that Van Dyke intended to draw his gun and shoot McDonald as he pulled up to the scene in his squad car.

"That was an essential element the prosecution needed to prove, and was able to do so," Romanucci said.

Activist Will Calloway, who sued the city to get the video released, broke down in tears as he spoke to reporters after the verdict.

"I know the whole country is looking at Chicago," he said. "It's only because of God that we got justice."

Calloway expressed disappointment in the city’s political establishment for not being more outspoken about the shooting.

“No black alderman showed up for this,” he said. “No black elected officials showed up for us.”

The Rev. Jesse Jackson, who attended several days of the trial, said the conviction provided a measure of justice, but it was "no time to celebrate or to rebel."

"There were police killings before Laquan’s murder and there have been police killings since," said the civil rights leader, who is based in Chicago. "We must challenge the system to end this egregious behavior toward young black people.

"Going forward, the name and fate of Jason Van Dyke should be a deterrent for police officers in Chicago and across the country."

Some critics have said the justice system is too lenient with police.

An officer in suburban St. Paul, Minnesota, was acquitted of manslaughter and dangerous discharge of a firearm last year in the 2016 shooting death of Philando Castille.

Castille was gunned down during a traffic stop as his girlfriend and her 4-year-old-daughter sat in the car.

Violent protests erupted in St. Louis last year after a former police officer was acquitted in the 2011 shooting of black motorist Anthony Lamar Smith.

Former Officer Jason Stockley said he believed Smith was reaching for a gun in his car. Prosecutors accused the officer of planting a silver revolver to justify the shooting.

Three Baltimore police officers were acquitted in the 2015 death of Freddie Gray in police custody, and Baltimore State's Attorney Marilyn Mosby dropped charges against three other officers involved in the incident.

Ahead of the verdict, Mayor Rahm Emanuel called on residents to respond peacefully. The police department canceled officers’ days off and stretched workdays to 12 hours to ensure they would have enough manpower in case things went south.

After the verdict, Emanuel and Police Superintendent Eddie Johnson issued a joint statement.

"Let us continue to hear each other and partner with each other – as public servants, police and members of the public," they said. "While the jury has heard the case and reached their conclusion, our collective work is not done. The effort to drive lasting reform and rebuild bonds of trust between residents and police must carry on with vigor."

Some activists had expressed concern that an acquittal or hung jury would demoralize the black community.

“If this case can’t lead to a conviction, I just don’t know how you can encourage people to have trust in the criminal justice system,” said the Rev. Marshall Hatch, a pastor on the city West Side and a critic of the police department.

Frank Chapman, an activist with the Chicago Alliance Against Racist and Political Repression, cautioned an acquittal of Van Dyke might spur unrest. His group was part of a coalition that planned demonstrations in the aftermath of the verdict.

"If you don't want things to burn, if you don't want people to be raising hell, then do the right thing," he said. “Don’t ask us to police for you. Do the right thing. Quit killing people. Quit mistreating people and then these things will not happen.”

Two other officers and a detective involved in the McDonald shooting face state charges of conspiracy, obstruction of justice and misconduct.

Officers Joseph Walsh and Thomas Gaffney are accused of lying to investigators and mischaracterizing the video recordings in hopes that independent investigators wouldn’t learn what happened and the public would not see the footage, according to an indictment.

Detective David March signed off on statements that several officers at the scene gave following the shooting and indicated in his report there were no discrepancies between what the officers said happened and what could be seen in the police dashcam video.

The three are scheduled to go to trial in November.