CHICAGO – Prosecutors said Chicago Police Officer Jason Van Dyke showed no regard for Laquan McDonald's life when he approached the black teen in October 2014.

Van Dyke's defense said the veteran cop had no choice but to fire a barrage of bullets at the troubled 17-year-old.

The sides made closing statements Thursday in the trial of Van Dyke, charged with first-degree murder in the controversial shooting death of McDonald. After two weeks of testimony in Cook County Circuit Court, the case now goes to a 12-member jury.

Chicago police, meanwhile, are bracing for protests.

Assistant Special Prosecutor Jody Gleason told jurors that Van Dyke showed "indifference to the value of Laquan's life" when he fired 16 bullets at the teen. She said Van Dyke's defense centered on "exaggerating the threat and hiding behind the police shield."

“He shot too early," Gleason said. "He shot too often. And he shot way too long.”

The shooting on a fall night on the southwest side of Chicago was captured on police dashcam video – chilling footage that strained already fraught police relations in the African-American community.

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. It appears to show McDonald moving away from officers when Van Dyke opened fire.

Van Dyke is charged with first-degree murder, 16 counts of aggravated battery and official misconduct. If convicted of first-degree murder, he could be sentencedto life in prison.

Judge Vincent Gaughan told jurors that they may also find the officer guilty of the lesser charge of second-degree murder. That charge carries a sentence of four to 20 years.

The jurors, who are being sequestered overnight at an area hotel, deliberated for about five hours Thursday and will continue their discussions about the case Friday.

Van Dyke's lead defense attorney told jurors that the police video – the centerpiece of the prosecution's case – was "essentially meaningless" because it failed to show the officer's perspective.

"We have to look at this from Jason Van Dyke's perspective," attorney Daniel Herbert said. "Probable guilt is not enough. That video is not enough."

Van Dyke's defense team says he acted to preserve his and fellow officers’ lives but became a political scapegoat during a difficult period for policing in America.

The shooting is one of several deadly encounters between police and black men and women in recent years that together have spurred a broader national conversation about law enforcement tactics in predominantly African-American communities.

During the trial, Van Dyke's defense team attempted to underscore 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 and had PCP in his blood at the time of his death.

A pharmacologist testifying for the defense said the PCP 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 testified that McDonald looked “deranged.”

Police encountered McDonald after receiving calls that a young man fitting his description had been breaking into vehicles and stealing radios from a truck lot on the city’s southwest side. They say he was found with a retractable knife with a 3-inch blade.

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

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Police say McDonald did not comply with repeated orders to drop the weapon and continued to wind his way through the city streets. At one point, he used the knife to scratch the windshield and pop the tire of a police car.

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.

Laurence Miller, a forensic psychologist, evaluated Van Dyke at the behest of the defense.

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.”

Two alternate jurors were dismissed from their duties Thursday. They said they found the prosecution's case against Van Dyke compelling.

Had they been regular members of the jury, they told reporters, they would have leaned toward convicting the officer.

"Shooting someone 16 times, that's a lot," one dimissed juror said.

The other dismissed juror told reporters that she thought the defense's focus on McDonald's past violence and drug use was irrelevant.

“Whatever he was doing that night doesn’t come into play into his final moments of his life," she said. "Jason Van Dyke didn’t know. … He had very limited information.”

Van Dyke jumped out of his squad car and opened fire moments after arriving at the scene.

The officer fired within six seconds of exiting the vehicle. In about 1.6 seconds McDonald was on the ground, never to get up again. Van Dyke fired for another 12.5 seconds, emptying his clip.

Van Dyke, who testified Tuesday in his own defense, said he continued to fire at McDonald because the teen was trying to get up.

Just before he opened fire, he said, McDonald raised the knife from his waist to above his shoulder.

That movement does not appear in the police video that was shown repeatedly to jurors throughout the trial.

“The video doesn’t show my perspective,” Van Dyke said under cross-examination.

Gleason refuted Van Dyke's account in her closing statement.

"Laquan McDonald was never going to walk home that night," she said. "The defendant decided that on the way to the scene when he told his partner, 'I guess we’ll have to shoot him.' "

Herbert, the defense attorney, told the jury the shooting was a "tragedy but not a murder."

"It’s a tragedy that could’ve been prevented with one simple step," he said.

He picked up McDonald's knife and dropped it to the courtroom floor.

"Laquan McDonald was the author, choreographer of this story," he said. "Remember the right decision isn’t always the easiest decision.”

As the jury deliberates, Chicago Police are bracing for protests.

The Rev. Michael Pfleger, a Catholic priest and activist, took to social media this week to call on Chicagoans to “SHUT DOWN” the city if the jury does not convict Van Dyke.

“Anything Less than a CONVICTION, the next day Chicago should SHUT DOWN… NO ONE SHOULD GO TO WORK, SCHOOL, ANY STORES….A COMPLETE SHUT DOWN,” Pfelger wrote.

Activist William Calloway, a plaintiff in the lawsuit that forced the city to release the video, called for peaceful protests if Van Dyke is acquitted.

“We want people to rise up,” Calloway said.

The police department’s relationship in the African-American community has 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.

The Rev. Gregory Livingston, a pastor who has led several protests in the city to spotlight concerns about policing in Chicago, said the Van Dyke trial is about “black Chicago versus the Chicago Police Department.”

“What it’s symbolic of is the unequal application of justice that has existed in Chicago in the black community,” Livingston said. “So even though he’s a police officer, what has to happen here in order for the black community to have some sense of justice is that no one is seen to be above the law.”

As Judge Gaughan was preparing to dismiss jurors for the evening Thursday, Van Dyke was several minutes late making his way back to court.

Assistant defense attorney Randy Rueckert said Van Dyke was tardy because one of his two young daughters had been threatened at school. Van Dyke went to make sure she was safe.

Gaughan scolded Van Dyke for being late, and told him to provide proof of the threat when court resumes Friday.

The judge warned that if Van Dyke doesn't have some documentation of the threat he might raise or revoke his bail.