The RCMP say the gunman who shot and killed a soldier before storming Parliament Hill had prepared a “video recording” prior to Wednesday’s attack in Ottawa.

In a statement released Sunday evening, RCMP said they have identified “persuasive evidence” that show Michael Zehaf-Bibeau’s attack was “driven by ideological and political motives.”

“Zehaf-Bibeau had prepared a video recording of himself just prior to conducting this attack,” the statement said. “The RCMP is conducting a detailed analysis of the video for evidence and intelligence.”

The video is not being released at this time, authorities said.

The RCMP statement said investigators are still looking into the origin of the gun used in the attack, but that they believe a knife carried by Zehaf-Bibeau was retrieved from his aunt’s property in Mont Tremblant.

The statement also said RCMP had identified the “source of funds” for Zehaf-Bibeau’s “pre-attack activities.”

“Zehaf-Bibeau had been employed in the oilfields of Alberta and had saved his money. He had access to a considerable amount of funds. We are investigating all of his disbursements in the period leading up to the attack,” the statement said.

The Ontario Provincial Police will lead an independent investigation into the events that occurred in Ottawa Wednesday, when security personnel at Parliament Hill shot and killed Zehaf-Bibeau after he had breached Centre Block.

The OPP will conduct their investigation at the request of the RCMP, a spokesperson confirmed to CTV News Sunday.

Mounties and Parliament Hill security staff shot and killed Michael Zehaf-Bibeau in the Hall of Honour, steps away from where MPs from all three political parties were holding their weekly caucus meetings.

Zehaf-Bibeau had forced his way into Parliament Hill's Centre Block, after gunning down Cpl. Nathan Cirillo at the nearby National War Memorial.

Officials say 70 rounds of ammunition were fired at Zehaf-Bibeau in the shootout.

Sergeant-at-Arms Kevin Vickers was hailed as hero earlier this week for shooting Zehaf-Bibeau dead. MPs have also credited Const. Samearn Son, a parliamentary security guard, with hampering Zehaf-Bibeau's ability to carry out his attack.

Son grappled with Zehaf-Bibeau outside the Hall of Honour, trying to wrest away the gunman's long rifle. Officials say Son forced Zehaf-Bibeau to point the gun at the ground and it went off, striking Son in the leg.

Firearms experts say Zehaf-Bibeau's weapon, a .30-30 Winchester rifle, is a slow-loading model better suited to hunting than firing at police. Forcing him to fire the weapon meant he had to manually re-cock it before firing another shot.

MPs say that delay may have significantly slowed Zehaf-Bibeau's attack.

Son told CTV's Katie Simpson that he's recovering well from his leg injury. "I'm good, I'll make a full recovery," he said Saturday, while walking into his house with the support of crutches.

In addition to the OPP investigation, House of Commons Speaker Andrew Scheer has ordered a full review of Parliament Hill security following the incident.

Meanwhile, recently released audio recordings from emergency scanners as the attacks were unfolding in Ottawa paint a more detailed picture about what happened after the first shots were fired at the National War Memorial.

"We may have multiple patients. One soldier has been hit," says a voice over the radio.

At that time, police were still unsure if other suspects were on the loose and all firefighters were ordered to return to their stations.

‘Acted in despair’

While investigators continue to examine what motivated the attack, the gunman’s mother has spoken out, painting a picture of Zehaf-Bibeau as a troubled man who was looking to start a new life in overseas but was pushed over the edge after being refused a passport.

In a letter to Postmedia that was published online, Susan Bibeau wrote that she believes her son was an “unhappy person at odds with the world.” She said that when they had recently connected after being estranged for five years, he had told her he ultimately wanted to go to Saudi Arabia, not Syria as the RCMP previously reported, and study Islam.

She suggested that her son’s mental illness and his history of drug addiction was “at the centre of this tragedy.”

“I don’t believe he was part of an organization or acted on behalf of some grand ideology or for a political motive,” Susan Bibeau wrote. “I believe he acted in despair.”

With files from CTV's Katie Simpson