RCMP Commissioner Bob Paulson says he hopes "someday" to make public a video left behind by gunman Michael Zehaf-Bibeau before last week's attack on the National War Memorial and Parliament Hill.

The country's top Mountie said Zehaf-Bibeau was "quite lucid and quite purposeful" in the video and that it contains evidence the shooting was driven by political and ideological motives.

Paulson said the video, as reported Sunday by CBC News, was broadly related to Canadian foreign policy and that the gunman makes reference to "Allah" in the video.

He said the video, which is still being analyzed by police, appeared to have been made "on [Zehaf-Bibeau's] own device."

"Our belief is that it has not gone anywhere else, but it may have gone elsewhere," Paulson said in remarks to reporters after his appearance Monday before the Senate's national security committee.

News of the video first emerged late Sunday when the RCMP issued a statement announcing its existence and describing it as evidence that Zehaf Bibeau was "driven by ideological and political motives."

Pauslon said investigators don't yet know if Zehaf-Bibeau shared his intentions to launch a violent attack. He added RCMP are working on a "detailed timeline" to satisfy themselves no one else was involved.

Paulson also said he doesn't believe Zehaf-Bibeau was wearing body armour during Wednesday's attack.

Preventing radicalization key, RCMP chief tells committee

Inside the committee room, Paulson told senators that is "extremely difficult to detect the early signs of radicalization, and ultimately determine if an individual may be preparing to launch an attack."

In fact, he noted, "the more elaborate the plot," the more chance there is that it can be interrupted during the planning process.

"The events of last week are clear examples of just how suddenly these attacks can occur and how unpredictable radicalized individuals can be," he told the committee.

"These acts were carried out with no advance warning, and thus far, seemingly little to no preparation."

He stressed the need for family members and friends to watch for "warning signals" of possible radicalization, including increasing isolation, or espousing of extremist or violent views.

"The best way to prevent terrorism is to prevent radicalization in the first place."

When asked about possible legislative changes, Paulson suggested that the threshold for obtaining a peace bond could be lowered, and the process streamlined with regard to the current requirement to get the consent of the Attorney General.

"I think there's an argument to be made that cops can handle that," he said.

The Senate national security committee, which launched its study of security threats before last week's attack, also heard from Michael Peirce, the assistant director of the Canadian Security Intelligence Service.

On Monday afternoon, Public Safety Minister Steven Blaney introduced a bill that would strengthen the powers of Canada's spy agency to monitor and track people suspected of plotting terrorist attacks.