Johnson had worked his way up the ranks in his three decades with the department. While testifying in 2017 at a trial over a police shooting, Johnson revealed that a dozen years earlier when he was a detective sergeant, he suffered a graze wound to his head when he chased on foot after a suspect who had tried to carjack him at gunpoint while working off-duty in a plainclothes security job for a South Side business. The suspect fired four shots at Johnson, who took cover with his weapon drawn but didn’t return fire, a department spokesman said at the time.