CHICAGO - Police officers who watched a colleague shoot a black teenager 16 times filed reports depicting a version of events different from what dashcam footage showed, portraying the teen as far more menacing than he appeared in the video.

The city released hundreds of pages of documents late Friday pertaining to the October 2014 killing of Laquan McDonald, 17, by Jason Van Dyke, a white police officer. Van Dyke was charged with first-degree murder last month, hours before the department released the video under a court order, sparking protests and accusations of a cover-up.

The video, which the city kept from the public for more than a year, shows McDonald veering away from officers on a four-lane street when Van Dyke, seconds after exiting his squad car, fires at close range. The officer continues shooting after McDonald crumples to the ground and is barely moving. The video does not include sound, which authorities have not explained.

In the newly released police reports, several officers, including Van Dyke and his partner, described McDonald as aggressively approaching officers while armed with a knife. At least three other officers, including his partner, supported key details in Van Dyke's portrayal of events.

The officers' version, recorded in more than 300 pages of handwritten and typed reports, prompted police supervisors to rule at the time that McDonald's death was a justifiable homicide and within the use-of-force guidelines, even though the dashcam video also was available to them shortly after the shooting.

Van Dyke told an investigator McDonald was "swinging the knife in an aggressive, exaggerated manner" and "raised the knife across the chest" and pointed it at Van Dyke, according to one report. Multiple officers reported that even after McDonald was down, he kept trying to rise while holding the knife.

"In defense of his life, Van Dyke backpedaled and fired his handgun at McDonald, to stop the attack," one report reads. "McDonald fell to the ground but continued to move and continued to grasp the knife, refusing to let go of it."

Van Dyke told an investigator he feared McDonald would rush him with the knife or launch it at him.

What's on video and what the officers reported could all be true, said Dean Angelo, president of the Chicago police officer's union, because each officer had "a different perspective," which could vary significantly from the fixed car camera.

The Rev. Jesse Jackson said the documents show police "misrepresenting" what happened and called for an escalation of protests Sunday in the business district.