Several sources, who have requested anonymity, have confirmed to The Canadian Press that Michael Zehaf Bibeau was fatally wounded by Vickers near the door of the Parliamentary library.
Police have said that Vickers was involved in Wednesday's gunfight with Zehaf Bibeau.
Security video released by the RCMP on Thursday showed Zehaf Bibeau's deadly race from the National War Memorial after he shot Cpl. Nathan Cirillo and hijacked a ministerial car before bursting into the Parliament buildings.
He ran in to Parliament's Centre Block through the main entrance with RCMP officers in hot pursuit.
The RCMP is charged with assuring the security of the exterior of the Parliament buildings.
A security service source says the gunman was intercepted by a House of Commons security guard who unsuccessfully tried to wrestle his gun away from him.
The guard yelled "Gun!" to warn his colleagues and tried to yank the barrel of the weapon down but Zehaf Bibeau managed to fire, wounding the man.
The gunman then bolted several metres down the Hall of Honour with police and guards chasing him. Shots were fired.
Zehaf Bibeau, his body riddled with bullets, huddled behind a column by the Parliamentary library. It was there that Vickers fired the fatal shots.
The slaying of Cirillo was the second killing of a soldier this week.
On Monday, Warrant Officer Patrice Vincent, 53, was fatally injured when a man identified as Martin Rouleau used his vehicle to run him and a colleague down in a parking lot of a federal building south of Montreal.
Rouleau, 25, fled the scene but was later shot dead after a pursuit in which his car rolled over. Friends said he had become increasingly radicalized.