This Oct. 5, 2018 photo provided by the Cook County Sheriff's Office in Chicago, Ill., shows Jason Van Dyke. Van Dyke, a Chicago police Officer, was taken into custody and photographed, after jurors found him guilty of second-degree murder and aggravated battery in the 2014 shooting of black teenager Laquan McDonald, at the Leighton Criminal Court Building on Friday, Oct. 5, in Chicago. Credit: Cook County Sheriff's Office | AP

CHICAGO — Jason Van Dyke, a white Chicago police officer, was found guilty of second-degree murder on Friday, nearly four years after he shot and killed Laquan McDonald, a black 17-year-old holding a knife.

The violent encounter sparked intense demonstrations across the city after authorities released a video showing Van Dyke firing 16 shots at McDonald, which led to a sprawling federal investigation and helped force top officials from their jobs. The closely watched trial again highlighted the fraught relationship between this city’s police force and its residents, particularly people of color, as well as questions here and nationwide about how officers use deadly force.

Van Dyke — who was also found guilty on 16 charges of aggravated battery, one for each shot fired at McDonald — has said he feared for his life. His attorneys said McDonald, 17, would be alive if he had dropped the weapon. Prosecutors argued that McDonald’s death was not justified and accused Van Dyke of “exaggerating the threat.” Jurors found Van Dyke not guilty of official misconduct.

This verdict marks the latest in the seemingly endless shock waves stemming from McDonald’s death and the subsequent release of the video, which continue to reverberate across the city and dominated the second term of Chicago Mayor Rahm Emanuel, D.

After the footage was released in November 2015, Emanuel ousted his police superintendent, Garry McCarthy, who later said he was a fall guy and is now running for mayor. Voters then dismissed the prosecutor in the case, who waited a year to charge Van Dyke. The Justice Department launched an investigation, concluding in a scathing report last year that the department violates the constitutional rights of residents. A week before Van Dyke’s trial began, Emanuel announced he would not run for a third term.

On Friday, following the jury’s determination, demonstrators gathered in the city’s streets and celebrated the outcome. Dan Herbert, Van Dyke’s defense attorney, suggested that police officers will look at the trial and hesitate to fire their weapons in potentially dangerous situations, saying: “It is a sad day for law enforcement.”

Herbert said he felt the evidence did not support the verdict, but added that he felt “relieved” Van Dyke was not convicted of first-degree murder

“He’s standing,” he said of Van Dyke. “He’s a tough man. He knew the stakes. The knew the climate. We knew coming into it with a Cook County venue in this case with a Cook County jury there was not a chance.”

This trial has drawn particular scrutiny in part because of how rarely officers are charged with fatally shooting people on duty. Convictions are even less likely to follow, as officers have wide latitude under the law to use deadly force. In recent years, fatal shootings of civilians by police officers in Cincinnati, Milwaukee, North Charleston, South Carolina, and the Minneapolis area have spurred intense protests, followed by criminal charges, then by acquittals or deadlocked juries.

The verdict in Chicago is among the exceptions — and the second time in recent months that a jury has convicted a police officer in a controversial shooting. In August, a Texas jury found former Balch Springs, Texas Officer Roy Oliver guilty of murder for the April 2017 shooting of Jordan Edwards, a 15-year-old black boy who was shot as he sat in the passenger seat of a car that was driving away from a house party. Oliver was sentenced to 15 years in prison. Such outcomes are are rare. An ongoing Washington Post database has found that on-duty police officers fatally shoot just under 1,000 people each year. A Post analysis of on-duty shootings between 2005 and 2015 found just 54 police officers had been charged in connection with such a shooting. Of those officers, just 16 were convicted.

McDonald’s death in October 2014 — just weeks after a black teenager was killed by a white police officer in Ferguson, Missouri, — did not draw nationwide attention until, 13 months later, the court ordered the release of the police dash-cam video. Authorities had initially said McDonald lunged at police officers, but the footage showed McDonald slowly walking down the middle of Pulaski Road before hitting the ground when he was struck by Van Dyke’s bullets. The police department has recommended firing officers for lying about McDonald’s death, and three current or former officers were indicted last year on charges of conspiring to cover up what happened.

Van Dyke remains an inactive officer on unpaid leave, the department said Friday, pending the Chicago Police Board’s review of the recommendation from Eddie Johnson, the police superintendent, that he be fired.

In a statement after the verdict, Johnson and Emanuel called for police, officials and residents alike to “continue to hear each other and partner with each other.”

“While the jury has heard the case and reached their conclusion, our collective work is not done,” they said. “The effort to drive lasting reform and build bonds of trust between residents and police must carry on with vigor.”

After the video’s released in November 2015 — the same day Van Dyke was charged with first-degree murder — protesters marched on downtown Chicago streets throughout Emanuel’s term. They gathered in front of the mayor’s home, on Lake Shore Drive and even on two lanes of the Dan Ryan Expressway to call attention to police reform and what they charged was a coverup from city hall.

City officials had fought releasing the tape in court, and it was only released after Emanuel won reelection to a second term and after Chicago’s City Council approved a $5 million settlement with the McDonald family.

Last year, the city borrowed $225 million on police-related settlements and judgments, bringing the total to $709 million between 2010 and 2017, according to a report by the Action Center on Race and the Economy. The organization estimates that the borrowing will eventually cost Chicago taxpayers more than $1 billion in interest for the life of the bonds.

Tensions surrounding the Van Dyke trial have been high. Protesters have gathered outside the George N. Leighton Criminal Courthouse every day of the three-week trial. Some high-rise owners in downtown Chicago have warned residents of potential violence following the verdict.

In a joint statement, activist Carl Dix and philosopher Cornel West called Van Dyke’s actions “illegitimate violence” that the trial “reinforced.”

“If the court lets Van Dyke walk free, that would be illegitimate violence too – a threat against every black and brown youth in Chicago,” they said. Some activists have argued for peaceful protests in the form of an economic boycott.

Washington Post writer Wesley Lowery contributed to this report.

Follow the Bangor Daily News on Facebook for the latest Maine news.