Ottawa shooter Michael Zehaf-Bibeau had "ideological and political motives" for Wednesday's attack, the Royal Canadian Mounted Police said in a statement on Sunday.
Zehaf-Bibeau opened fire near Canada's Parliament building and fatally shot a soldier before being killed by a sergeant-at-arms.
Prime Minister Stephen Harper has labeled the attack an act of terrorism.
Designated a high-risk traveler, the shooter had been barred from leaving the country. U.S. officials said that he recently converted to Islam.
Police said that they have "persuasive evidence" of Zehaf-Bibeau's political motives. According to police, Zehaf-Bibeau had recorded a video of himself prior to the attack that provided some clues. The statement also provided more information on the shooter's weapons and finances.