They didn't know each other and their respective attacks were not directly linked. But Martin Couture-Rouleau and Michael Zehaf-Bibeau shared common traits — both self radicalized and adrift in their lives and connected in their sympathy to radical Islamic ideology, seeking to venture overseas and possibly fight for what they considered a higher cause. 

"They're both lone wolves," said Lorne Dawson, co-director of the Canadian Network for Research on Terrorism, Security and Society. "Both a bit more impulsive, bit more opportunistic, if there was planning, it's amateurish."

Couture-Rouleau waited in a parking lot for at least two hours before driving his car into two Canadian soldiers, killing Warrant Officer Patrice Vincent, Two days later, Zehaf-Bibeau, armed with a Winchester .30-30 calibre rifle, fatally shot Cpl. Nathan Cirillo as he guarded the National War Memorial before storming  Parliament Hill.

"Mr. Rouleau [committed the attack] where he lived," said Michael Zekulin, a political science professor who studies terrorism and radicalization at the University of Calgary. "Mr. Bibeau, he was on the move. He was all over the place. He didn't live anywhere. There wasn't that same attachment. Mr. Rouleau seems a little more opportunistic. Whereas Mr. Bibeau seems a little more 'I'm just going to shoot the first soldier I see ... and then move on to Parliament.'"

"Going directly to Parliament is much more symbolic and is a much more powerful message than Mr. Rouleau running down people in a parking lot of a mall," Zekulin said. "Both are making a statement but if you're going to compare them, both get soldiers but one gets a soldier on Parliament Hill then proceeds into the institution of government."

They were known to authorities. Although Zehaf-Bibeau launched the more brazen attack, police considered Couture-Rouleau the bigger threat of the two, naming him as one of the 90 suspected extremists who the RCMP believed intended to join militants fighting abroad.

Couture-Rouleau also had a much larger online presence than Zehaf-Bibeau and had posted propaganda videos and other materials admiring jihad — or “holy war” against enemies of Islam — on his Facebook profile page, including a video featuring the logo for ISIS.

Zehaf-Bibeau's online activities are much less known but officials say he had visited extremist websites and interacted with individuals on those sites.

Tangled with authorities over passport

Couture-Rouleau and Zehaf-Bibeau also tangled with authorities over their passport. Couture-Rouleau's passport was seized after he was arrested at the airport in July while on his way to Turkey. Zehaf-Bibeau was apparently frustrated over the time it was taking to obtain a Canadian passport and the time it would take to get a Libyan passport. The RCMP said passport issues likely played a role in both the attacks.

Both men converted to Islam as adults — Couture-Rouleau last year and Zehaf-Bibeau some years earlier. Couture-Rouleau was an occasional attendee to his Quebec mosque, had stopped going about two months ago and kept to himself, apparently never giving any hint of his radicalized beliefs, the Globe and Mail reported.

Although Zehalf-Bibeau also kept to himself at the B.C. mosque he attended in 2011 for three to four months, he was more vocal, and expressed his objection to its policy of accepting non-Muslims. (He was asked to leave in 2012 after trying to sleep there following some time spent in jail.)

But where Couture-Rouleau appears to have had no criminal record, Zehalf-Bibeau had a history of getting in trouble with the law, in both Quebec and B.C. and had pleaded guilty to charges including drug possession and robbery, and had a history of battling substance abuse. 

Couture-Rouleau's issues seemed more domestic and financial in nature. He was apparently having problems with his estranged wife and was facing financial constraints following the failure of his pressure washing business.

Both came from divorced families but Zehaf-Bibeau was also estranged from his family. His mother claimed that she had only spoken with him last week, having not seen him for over five years before that. Couture-Rouleau, however, lived with his father, his dad saying that he seemed fine the morning of the attacks, although acknowledging he had concerns about his beliefs. In fact, the RCMP said authorities had visited Couture-Rouleau after being notified by family members, who were concerned about his extremist views.

Exhibit similar traits

Zekulin notes that Zehaf-Bibeau and Couture-Rouleau exhibited similar traits —​ relatively recent converts to Islam, coming from broken families, personal problems.

But he says these similarities just aren't consistent enough to help pick out these types of people. Radicalized individuals can come from well-adjusted backgrounds. People who have trouble with the law or have a history of drug abuse or come from broken families or are recent converts — none of those are necessarily markers to predict extreme behaviour.

"The reality is that if you were to stack that up into large samples of individuals, they're not all going to look like this," Zekulin said.