In Ottawa on Oct. 22 Cpl. Nathan Cirillo was shot and killed in front of the War Memorial by gunman Michael Zehaf-Bibeau.
The area surrounding Parliament was put on lock down as police began their investigation and the neighboring office buildings, construction sites and restaurants were evacuated.
As Bibeau made his way into the Parliament buildings politicians barricaded the doors of the caucus room while authorities pursued Bibeau through Center Block.
But Bibeau's attack came to a sudden end as Sergeant at Arms Kevin Vickers ran out of his office, pistol in hand.