The account by a former supervisor and friend at a drilling company in Squamish, B.C. also reveals that Zehaf-Bibeau was open about his support for jihadi groups.
CBC has agreed not to reveal the man's identity.
The man first got to know the 27-year-old who called himself Mike Zehaf in 2007, when he arrived in Squamish. The work involved drilling and injecting shotcrete in underground tunnels. He worked closely with Zehaf-Bibeau as foreman of his small work crew for the next two years, until both were laid off on the same day when the project ended.
The two men worked together 13 hours a day, six days a week and carpooled to work as well. The foreman says Zehaf-Bibeau also sometimes accompanied him on dog walks and dined at his house a few times.
At the time, Zehaf-Bibeau was sharing a rented house with two other young men, both locals. He was making more than $90,000 a year, but was very focused on saving money, said the foreman. He spent little and drove a 1994 Nissan Pathfinder he said had been given to him by a man at a Vancouver Islamic centre.
"The Mike Zehaf I knew was a nice guy," he told CBC News. "Kind, friendly, polite and appreciative. He always had good manners, like a guy who was trying to impress the parents of a hot chick."
Zehaf-Bibeau was also devout, said the foreman, praying five times a day, every day.
"Sometimes you'd ask: 'Where's Mike?' And he would have just downed tools and he'd be off somewhere praying."
Zehaf-Bibeau also expressed disapproval of the partying lifestyle of his housemates, but on one occasion went out with co-workers and got drunk. Later he expressed regret and shame.
There were also episodes that hinted at a darker side.
The foreman said Zehaf-Bibeau made no secret of his political views, telling co-workers the Taliban were justified in resisting foreign occupation. On more than one occasion, he showed videos of Taliban ambushes or IED attacks on coalition forces. His co-workers didn't take the videos too seriously, the foreman said, partly because Zehaf-Bibeau was so open about it. "We told him he was being an idiot."
On one occasion at least, Zehaf-Bibeau joked about being a suicide bomber, running up to a co-worker while holding his coat tightly closed, then opening it and saying "BOOM!"
Only once did he become violent. It happened when a worker from the Philippines, who constantly needled Zehaf-Bibeau about "being dumb," pushed him too far. The foreman said Zehaf-Bibeau almost stabbed the man with a screwdriver.
Zehaf-Bibeau's style changed over the time the foreman knew him. At first, he wore what the foreman described as "thug"-type clothing and bragged about his gold chains. One photo the foreman shared with CBC News shows Zehaf-Bibeau relaxing in a Vancouver park wearing a tracksuit by Arab-American hip-hop designer El Wissam.
The records of the drilling company confirm it was engaged in the Squamish project during the period when Zehaf-Bibeau worked there. Metadata from the photographs date them to the same period.
By the end of his time in Squamish, he was coming to work in the long robe and keffiyeh of an Arab sheik. "But it was like he was wearing a costume," says the foreman.
The foreman says Zehaf-Bibeau spoke often of his time in Libya, where he lived with his father following his parents' separation. "He seemed to take more after his father's side."
One time, he told a Jewish co-worker he held a Libyan passport that said "Not valid for travel to the occupied state of Palestine." The next day, Zehaf-Bibeau brought the passport to work to prove it. The foreman said Zehaf-Bibeau never showed any animosity toward the worker on account of his Jewish faith.
The foreman said Zehaf-Bibeau spoke often of his desire to return to Libya. "He said he wanted to settle down there and find a wife."
Past drug use
Zehaf-Bibeau also spoke about being tested by God, the foreman recalled. "He used to say things like he didn't have that long, because God had plans for him, that kind of thing."
He says Zehaf-Bibeau was open about having had problems with drug use in the past. "But there's no way he was using crack when he was working with us. I am 100 per cent certain."
He also says he doesn't believe that Zehaf-Bibeau owned a rifle or hunted.
"He didn't know even how to use a wrench. Mike was the kind of guy who you would send out of the tunnel to bring you a hammer, and he would come back half an hour later with a big wrench and say he couldn't find the hammer, but hey, this is big, why don't you hit it with that?"
The foreman said when he learned on the news of Zehaf-Bibeau's attack, it crossed his mind that he should talk to police, given some of the views he had expressed and the videos he had shown.
What stopped him was a feeling it might be unfair. "It felt kind of like it would be racial profiling," he said.
"When I saw him on the news, my reaction was 'Wow! He actually went and did something.' I never would have believed it."
The foreman said that when the project came to an end in Squamish, both he and Zehaf-Bibeau were offered jobs on another tunnelling project to connect the Capilano reservoir to North Vancouver. The foreman declined, but recalls that Zehaf-Bibeau accepted. It's not clear how long he worked on that project, which is ongoing.
But Zehaf-Bibeau's life took a downward trajectory soon afterwards. His return to Vancouver coincided with a return to hard drug use. By the end of 2011 he was living in a homeless shelter in Vancouver, asking a judge to sentence him to prison.
"I'm a crack addict and at the same time I'm a religious person," Zehaf-Bibeau told the judge. "So I want to sacrifice freedom and good things for a year maybe, so when I come out, I'll appreciate the things of life more and be clean."
In spite of all the money he made in Squamish, Zehaf-Bibeau told the judge he had no income to pay a $100 victim surcharge on a charge of uttering threats, after he held up a McDonald's restaurant to force police to arrest him.
But Zehaf-Bibeau may not have been honest about his financial situation. The RCMP revealed at the time of the attack on Parliament Hill that Zehaf-Bibeau still "had access to a considerable amount of funds."
RELATED ON HUFFPOST: