The sight of a cop emptying 16 bullets into the body of a black teenager was one Chicago police likely hoped the public would never see. But after a year-long battle to get dashcam footage released, viewers around the world on Tuesday night watched video of 17-year-old Laquan McDonald take his last steps before officer Jason Van Dyke buried him in a haze of bullets and gun smoke. Viewers struggled to understand why the 14-year veteran cop would repeatedly shoot a teenager who, though armed with a small knife, was walking away.