Last Updated Oct 23, 2014 4:56 PM EDT
As the investigation of Wednesday's shooting rampage in Ottawa continues, a U.S. law enforcement official told CBS News that the Canadian government was investigating whether the suspect was in contact with known militants in Syria -- possibly the Islamic State of Iraq and Syria (ISIS).
Royal Canadian Mounted Police commissioner Bob Paulson said Thursday that Michael Zehaf-Bibeau had recently applied for a passport, and authorities now believe he intended to go to Syria.
"The passport was part of his motivation. His application was not rejected. His passport was not revoked," Paulson said. "He was waiting to get it and there was an investigation going on to determine to see whether he would get a passport."
Police swarmed the streets after a gunman shot dead a soldier guarding the National War Memorial, reports CBS News correspondent Jim Axelrod. Witnesses said the man then stormed Canada's parliament, where he was killed.
On Thursday morning, Ottawa police said they were confident that only one gunman took part in the attack after previously saying that other shooters may have been involved.
The booming sounds of gunfire filled the halls of Canada's parliament as security forces spotted the suspected shooter.
Streams of people fled from the building as police rushed to secure the area.
The violent spree ended when 58-year-old sergeant-at-arms Kevin Vickers shot and killed the alleged gunman. Vickers has a ceremonial role but is credited for stopping the attack outside a caucus room where members of parliament were holding meetings.
Inside lawmakers used furniture to barricade themselves in rooms for protection.
A Parliament Hill reporter recorded the frenzied moments as the shooting began.
"I don't know, a bunch of gunshots... A guy with a shotgun [gunfire]. Where do we go?! Where do we go?!"
The attack started just steps away at Canada's war memorial. That's where police say the suspect shot a soldier standing guard, at point blank range.
Law enforcement and U.S. government sources told CBS News the suspect was born in Quebec in 1982. He is from British Columbia and recently converted to Islam. Sources said he had a history of drug addiction prior to his conversion.
No further information was available on Bibeau's apparent contacts with people in Syria, but hundreds of Westerners have traveled to Iraq and Syria to join Islamic extremist groups fighting against the governments of those countries. Many have heeded the call to jihad made in hours and hours of well-crafted propaganda videos posted online by groups including ISIS.
"We were working on the statue, and I heard a bunch of pops. I look across the street and there's a man with a rifle shooting at a bunch of people," a construction worker who witnessed the incident said.
Emergency responders performed CPR but Cpl. Nathan Cirillo was killed.
A dash cam video allegedly shows the suspect getting into a vehicle with no license plates, holding what appears to be a weapon. Multiple eye witnesses describe the man as dressed in black with a scarf over his face.
"Let there be no misunderstanding: We will not be intimidated. Canada will never be intimidated," Prime Minister Stephen Harper said in a national address Wednesday evening.
He called the shooter a terrorist.
"This week's events are a grim reminder that Canada is not immune to the types of terrorist attacks we have seen elsewhere around the world," Harper said.
"We have a tremendous country, if you travel the world, we got it pretty darn good here, and I hope this doesn't change it," parliamentarian John McKay said.
This is the second violent attack on Canadian soil this week.
On Monday, a radical jihadi deliberately ran over two Canadian soldiers, killing one. That suspect was also shot and killed following a police chase.