By Lee Carter
BBC News, Toronto
A sense of profound shock over this week's shooting rampage by a gunman at a Montreal college is slowly giving way to a growing demand for explanations about how such a tragedy could have happened and whether more could have been done to prevent it.
An 18-year-old woman died and 20 other people were injured, several critically, when 25-year-old Kimveer Gill walked purposefully up to the entrance of Dawson College and opened fire on students, both outside and inside the building.
The gunman killed student Anastasia De Sousa
He finally turned the gun on himself after being cornered and shot by police.
Images splashed across the front pages of Canadian newspapers, taken from Mr Gill's online diary on a goth subculture website (since removed), showed him in various poses brandishing a Baretta CX4 semi-automatic weapon while wearing a long black trenchcoat and large army boots.
The entries in the diary build a picture of a loner who disliked most people, had been bullied at school and was fascinated with violent video games and movies such as Natural Born Killers.
An investigative report by the French-Canadian news network RDI shows that Canadian government records disclose that Mr Gill had legally purchased the weapon and at least two others, officially registering them in his name.
The revelation that such a disturbed young man could have obtained the kind of weaponry the laws are supposedly designed to keep out of such individuals' hands is re-igniting the debate over the country's gun control laws.
And it comes just as Canada's Conservative Prime Minister, Stephen Harper, is preparing to introduce legislation to scrap a controversial gun registry of every firearms-owner in the country not previously registered by existing regulations.
The registry, introduced by a previous Liberal government, has proven costly and bureaucratic.
Opponents have criticised it for victimising rural law-abiding gun-owners who may own no more than a single hunting-rifle instead of directing resources to the growing problem of criminals smuggling illegal and dangerous weapons from the United States.
Mr Harper hinted that the registry had failed in the case of the Montreal shooting.
"I would say simply, the legislation that is in force today, did not prevent this incident and the government is trying to find more effective legislation in the future," he said.
The president of the country's Coalition For Gun Control, Wendy Cukier, acknowledged that the existing laws had not managed to screen the Montreal gunman but said that this was not an argument to scrap the registry.
"This whole notion that you can draw this nice clean line between criminals and law-abiding owners ignores the fact that someone like the killer on Wednesday was apparently a 'law-abiding gun-owner' until he shot 20 people," she said.
Quebec's provincial Premier, Jean Charest, has also weighed in on the debate over the registry, arguing that if it has the capacity to save even a few lives, it is worth keeping.
Montreal is part of the province and despite the fact that the registry's abolition was one of Mr Harper's election promises when his party formed a minority government at the beginning of 2006, he also needs voter support in Quebec if he hopes to form a majority the next time he goes to the polls.
Campus security has been another issue brought to the fore by the 13 September shooting in Montreal.
Despite criticisms from its student union that Dawson College staff were not at hand in the aftermath of the shooting, the school's director, Richard Filion, insisted that the college had responded appropriately.
"There will be criticisms, but I don't believe we made any errors," he told reporters.
"I'm convinced that we reacted in the best we could, given the exceptional circumstances. I've been told that as far as security is concerned, we did everything we are supposed to."
Many Canadian campuses have increased their security and introduced their own community policing. But Robert Steiner, a spokesperson for The University of Toronto and a member of its crisis management team, believes that there are limits to security.
"You can't make a university into an armed camp because it should be a place where all sorts of different people can come together and relax enough with each other to be able to focus on discussion, discovery and discourse. You can't turn it into an airport," he said.
The balance, says Mr Steiner, will continue to be somewhere between creating a safe environment with an open one.