The shooting, which triggered a lockdown of the nation's capital, came just two days after a terror attack in Quebec.
A government official told Fox that investigators believe Zehaf-Bibeau, who was killed at the scene, had changed his name from Joseph Michael Hall. U.S. agencies also have been advised he was believed to be a convert to Islam from Quebec.
Counter terrorism investigators are reviewing his social media traffic and profile, with a focus on any link to the attack on two soldiers in Quebec Monday.
The Toronto Globe and Mail said sources had told the paper Zehaf-Bibeau was recently designated a "high-risk traveler" by the Canadian government and his passport had been seized.
By Wednesday night, three persons who had been taken to Ottawa Hospital with minor injuries were all released.
Canadian Prime Minister Stephen Harper said in a national television address Wednesday night that the attack was "a grim reminder Canada is not immune to the kind of terrorist attacks we've seen around the world."