But when his passport application was repeatedly denied, Zehaf-Bibeau felt trapped, "unable to stay in the life he was in, unable to move on to the next one he wanted to go to", his mother wrote.
"He was mad and felt trapped so the only way out was death." She stressed that, while "horrified" by her son's actions, he had suffered from deep psychological problems.
Zehaf-Bibeau killed a soldier and attempted to storm parliament before the assembly's sergeant-at-arms shot him dead.
The attack - the second in a week targeting Canadian military personnel on home soil - came as Canadian jets were to join the US-led bombing campaign against Islamist militants in Iraq.
Police were investigating Zehaf-Bibeau's interactions with "numerous individuals" in the days leading up to the attack, Paulson said, adding that the young Canadian had saved up a considerable amount of money from working in oil fields.
- AAP