Ottawa police have released dramatic surveillance footage showing the moments the gunman breached security and attacked Canada's parliament on Wednesday.
The video surveillance footage showed how the young gunman took less than four minutes to gun down army reservist Corporal Nathan Cirillo and make his way into parliament, where he exchanged fire with police and parliamentary security.
Watch: Canadian parliament shooter in action
The footage emerged as officials said they had found no evidence of a wider plot following another deadly attack on Monday -- also by a young Canadian convert to Islam who had sought to leave for Syria.
The prospect of more such strikes was at the forefront of many minds in Canada, as a society proud of its reputation for openness and tolerance grappled with a new menace.
Canadian authorities were scrambling to probe the background of the young men, the first of whom ran his car over a soldier, killing him, and another who shot the soldier at a war memorial before storming parliament and being gunned down.
"These are difficult threats to detect," Royal Canadian Mounted police commissioner Bob Paulson said. "There is no way of knowing where or when such an attack could take place."
Paulson said the gunman in Wednesday's attack on parliament, identified as 32-year-old Michael Zehaf-Bibeau, had been in Ottawa applying for a passport to travel to war-torn Syria.
It remained unclear whether Zehaf-Bibeau "received any support in the planning of his attack," he added.
In the House of Commons on Thursday, members applauded Sergeant-at-Arms Kevin Vickers, who fired the shot that stopped Zehaf-Bibeau.
Vickers, a veteran of the Royal Canadian Mountain Police appointed to lead the parliamentary security team and wield the ceremonial mace, has become an inspiration to Canadians struggling to comprehend how two of their countrymen could turn against their homeland.
A man identified by Royal Canadian Mounted Police as Michael Zehaf-Bibeau is seen on Wednesday as he exits a car and runs toward the parliament buildings in a still image taken from surveillance video released by the RCMP. REUTERS
"The objective of these attacks was to instill fear and panic in our country and to interrupt the business of government," Prime Minister Stephen Harper told the chamber as business resumed.
"Well, members, as I said... Canadians will not be intimidated. We will be vigilant but we will not run scared."
"We will be prudent but we will not panic and as for the business of government, well, here we are, in our seats, in our chamber in the very heart of our democracy and our work."
Harper then crossed the floor to shake Vickers' hand, and to hug opposition leaders.