A Chicago police officer accused of shooting a black teenager sixteen times will be tried for murder.

Officer Jason Van Dyke was formally charged Tuesday with the murder of 17-year-old Laquan McDonald.

It’s the first time a Chicago officer has been charged with first-degree murder for an on-duty shooting in almost 35 years. But it’s not the first time authorities have investigated Van Dyke, who was reportedly the subject of at least 18 civilian complaints—none of which resulted in disciplinary action.

Which could explain why Van Dyke wasn’t indicted until the autopsy was made public amidst reports of a graphic dashcam video, described by one witness as “an execution.”

The incident reportedly began on Oct. 20, 2014, when Van Dyke responded to a call about an armed man in a Burger King parking lot. It ended, sixteen shots later, with McDonald lying dead on the ground.

The official police story—that Van Dyke fired after McDonald, who had PCP in his system, lunged at him with a knife—quickly fell apart.

Autopsy results showed McDonald had been hit not once—as initial reports claimed—but sixteen times, in the head, neck, torso, back, arms, groin and legs.

The graphic video, which has been viewed by attorneys for the McDonald family, reportedly shows McDonald was walking away when Van Dyke began firing. Van Dyke is said to continue shooting at McDonald, even after the teenager fell to the ground in a fetal position.

Attorneys for the family provided this description to the Chicago Sun-Times:

“He is walking. … When the officer begins shooting, the first shots spin McDonald around. The officer continues to fire from a distance of between 12 and 15 feet. McDonald falls. The only movement is the puffs of smoke coming from the teen’s torso and his head. The police officer comes into view and kicks the knife out of the boy’s right hand.”

The video itself has been the subject of much litigation after the AP and a freelance journalist named Brandon Smith filed two separate Freedom of Information Act requests.

A Cook County judge finally ordered its release last week over vehement protests from the Chicago Police Department, which argued that making the video public would “hamper ongoing investigations.” The court-imposed deadline for the video’s release is tomorrow.

A lawyer for Van Dyke says his client feared for his life during the encounter and is “scared to death” the video’s release will lead to violence against himself, his wife and their two children.

The city has already settled with McDonald’s family for $5 million.

Image via AP. Contact the author at gabrielle@gawker.com.