An ex-military man now training to be a pastor at the Harbour Light Alliance Church in Cold Lake, Alta., Wayne Driver spoke to CBC News on Thursday about his son's troubled life.
Driver said he was in the parking lot of a local Shoppers Drug Mart when his daughter called his cellphone from London, Ont., with the news that his 24-year-old son was dead.
"When I found out the news that he was shot and killed, I wanted to die myself," he said.
He spent the night thinking about the past, about all the times he had lost his son over the years: first as a boy of seven, then as a troubled teenager, and now finally, irrevocably.
During a lengthy interview, Driver said he first lost his son 17 years ago, when the boy's mother died.
His son was born in Regina on Aug. 18, 1991. At the time, his parents had a farm near the city.
Driver said his son was a happy child, but definitely "a mama's boy" who developed an extremely close bond with his mother.
Aaron was seven when his mother died.
"That's when he got mad at the world," Driver said. "He blamed me for killing his mother. He stopped eating. He figured if he didn't eat he could go to be with his mother."
Over the next years, father and son grew even further apart.
A year and a half after his wife died, Driver remarried. He said his son wanted "nothing to do" with his stepmother.
The troubled boy grew into a more troubled teenager. He ran away from home, skipped school, stole from stores, had run-ins with police.
When he was 12 or 13, his father and stepmother, concerned about his behaviour, rummaged through his bedroom one day in search of a marijuana stash. Instead they discovered hateful poems the teenager had written about his desire to kill his parents.
By 2012, his parents were living in Winnipeg, and that year Aaron moved back in with them.
It was around then, Driver said, that his son discovered Islam.
"I actually thought Islam was a good thing for him. Because he had stopped the drugs, he had stopped the drinking. He actually stopped smoking and swearing."
At some point, Driver said, his son discovered a darker side to his new religion, though his parents at first had no idea.
"When I heard some of the videos he was listening to, I thought he was just learning the Muslim faith," Driver said. "And I thought it was a good thing. Because he had become a better human being for it."
In January 2015, agents from the Canadian Security Intelligence Service came to Cold Lake and met with Driver. They showed him a thick file that detailed, among other things, tweets his son had sent expressing radical beliefs, and lists of radical Facebook pages his son had visited.
"I didn't realize he was so radicalized," he said of his son. "I didn't know he could speak Arabic so well. I knew he was mad at the world because of his mother dying, but I didn't realize he was turning his hatred outward to the world."
'I wanted to die myself,' says father of Aaron Driver - Edmonton - CBC News