The Alberta Serious Incident Response Team said Thursday the officer did not commit a criminal offence, and described his response as heroic.
"The actions of the uniformed police officer in this incident likely saved the elderly couple from being more seriously injured," the agency said in a news release.
Police had stopped a suspicious vehicle outside a bank on May 14 when it started backing up, hit a parked police car then struck the seniors on a sidewalk.
The vehicle reversed and was heading towards the couple again when the uniformed officer fired two shots.
"One of the rounds struck the adult male in the head, causing the vehicle to stop," ASIRT said.
The 38-year-old driver survived but was left permanently blind.
The female pedestrian, who was 78 at the time, underwent surgery for a broken elbow and hip. Her husband was treated in hospital for minor injuries.
Jason Harron is facing several charges, including criminal negligence causing bodily harm and evading police. He has yet to go to trial.
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