Authorities said Walker had stopped the car because he ran out of gas and the passenger-side front tire had gone flat from driving over a curb, a stop sign, a large rock and then through at fence at 13800 S. 933 East, court records show. He then continued driving a few blocks away to the area of 13200 South, police said.
When Johnson pulled up near the Volvo to see if he could help, Walker allegedly shot Johnson through the open front passenger side window of Johnson's police vehicle.
Johnson was struck in the chest by the bullet and tried to drive away northbound. Walker, who was allegedly under the influence of methamphetamine at the time, fired at least three more shots, which struck Johnson's marked vehicle, court documents state.