According to News sources the attacker had been deprived of his passport by Canadian Authorities having attempted travel to Turkey and having been suspected of terrorist links. It seems he wasnt JUST a whacko.
So the question is....what do we need to do with these people? Apparently having stopped him travelling they had insufficient evidence to charge him with anything so he was free to act out his own little fatwah at home instead.
Perhaps we ought to let them travel out but ensure they never get back in.