Royal Canadian Mounted Police commissioner Bob Paulson said the video was “persuasive evidence that Michael Zehaf-Bibeau’s attack was driven by ideological and political motives”.
Mr Paulson said investigators also identified where the shooter obtained money for the car he bought and his pre-attack activities.
He said Zehaf-Bibeau, 32, had been employed in the oil fields in Alberta, saved his money, and had access to a considerable amount of funds.
Zehaf-Bibeau shot dead Corporal Nathan Cirillo, 24, who was assigned to the honour guard at the national war memorial. Zehaf-Bibeau was gunned down inside parliament by the sergeant-at-arms of the House of Commons, Kevin Vickers.
The attack in Ottawa came two days after a man described as an “Isil [Islamic State]-inspired terrorist” ran over two soldiers in a car park in Quebec, killing one and injuring the other before being shot dead by police.
The man had been under surveillance by authorities who feared he had jihadist ambitions and seized his passport when he tried to travel to Turkey.
Unlike the attacker in the Quebec case, Zehaf-Bibeau was not being watched by authorities. But Mr Paulson said last week that Zehaf-Bibeau, whose father was from Libya, may have lashed out in frustration over delays in getting his passport.
Mr Paulson said his mother told police her son had wanted to go Syria, but Susan Bibeau later denied that in a letter published by Postmedia News, saying her son told her he wanted to go to Saudi Arabia, where he could study the Quran.