The Chicago Police Department has released video footage of the officer-involved shooting of 17-year-old Laquan McDonald, who was struck 16 times during a confrontation with officers.

Chicago Mayor Rahm Emanuel urged calm as City Hall got set to release police dash cam footage from the shooting incident, which occurred in October 2014. During the incident, 37-year-old Jason Van Dyke, a white officer, shot and killed McDonald, an African-American teen.

Warning: The footage has been described as graphic.

From the black and white dash cam video, which features no audio, viewers can see the back of McDonald jaywalking along the middle of the road at 5:18, with his arm outstretched and holding a small knife. A police vehicle is seen approaching him to the left of the screen, and two officers get out with guns drawn.

As McDonald moves away from the officers, his body becomes the only one in the video frame. He can then be seen twisting around and falling to the ground. A puff of smoke lifts from his body as a bullet appears to strike. Without audio, there is no way of knowing what, if anything, was said. There is no way of knowing how many shots were fired simply from viewing the video. McDonald appears to move his arms several times.

At 5:45, another puff of smoke is seen leaving his body. At 5.51, a police officer comes into the frame to kick the knife out of McDonald’s hand. Another police vehicle drives up and at this point, because of the vehicle lights, what appear to be pools of water around the body, possibly blood, can be seen. Prosecutors said Officer Jason Van Dyke opened fire from about 15 feet and kept shooting after the teen fell to the ground.

Police initially said McDonald, who had PCP in his system when he died, was behaving erratically and refused police commands to drop a folding knife with a 3-inch blade. At the time of the shooting, the police union maintained the officer fired in fear of his life because the teen lunged at him and his partner with the knife.

“I understand people will be upset and want to protest when they see this video,” Emanuel told reporters during a Tuesday afternoon press conference. “It is fine to be passionate, but it is essential to remain peaceful,” Emanuel added.

Earlier in the day, Van Dyke became the first on-duty Chicago officer to be charged with first-degree murder. He was ordered held without bail at a hearing. He has been placed on a “no pay” status by the department.

The one-page criminal complaint lodged against Van Dyke charged him with shooting McDonald “without legal justification and with the intent to kill or do great bodily harm.” He could face a minimum of 20 years in prison if convicted.

Soon after the video was released, protesters began filling the streets. Some chanted, “16 shots!” in reference to the number of times McDonald was allegedly struck.