Several reports cite sources saying that Michael Zehaf Bibeau can be seen on security camera footage taking a tour of Centre Block on Oct. 4.
The Ottawa Citizen says a spokeswoman for Speaker Andrew Scheer confirms there is video footage from Oct. 4 and that it is part of the security review of the events of Oct. 22.
Cirillo was on ceremonial guard duty at the National War Memorial when he was shot dead by Bibeau.
Bibeau then stormed onto Parliament Hill, where he died in a gunfight in the Centre Block.
The RCMP has said it has evidence indicating Bibeau was driven by "ideological and political motives."