The head of Canada's Intelligence and Security Service appears again before the general committee investigating foreign interference in the elections after several witnesses indicated that the Canadian Security Intelligence Service (CSIS) did not inform them of the intelligence it gathered regarding Chinese interference.

The questions about who knows what regarding foreign interference in the elections are at the heart of the investigation's mission, which arose due to allegations that Prime Minister Justin Trudeau's government was aware of the foreign interference but chose not to act.

The first phase of the investigation was supposed to conclude on Wednesday, but CSIS Director David Vigneault will return to the podium this morning, Friday, at the request of some participants.

This summons comes after several witnesses told the investigation that he did not warn them about the seriousness of the threat, despite documents indicating otherwise.

At the core of this issue are warnings from CSIS in briefing notes that key witnesses claim they never received.

For example, one of the documents cited multiple times in the investigation states that CSIS believes the Chinese government intervened "secretly and deceitfully" in the federal elections of 2019 and 2021.

A briefing note issued in February 2023 indicated that China's interference was practical in nature and primarily focused on supporting those regarded as either "supporters of the People's Republic of China" or "neutral" on issues of concern to the Government of the People's Republic of China.

This document was prepared to be presented to the Prime Minister's Office.

During his testimony before the investigation on Wednesday, Trudeau stated that he had never seen that briefing note – echoing a claim made by Deputy Chief of Staff Brian Clow earlier in the week.

Clow stated on Tuesday, "Most of the information in that document was not conveyed to us in that meeting."

The CSIS document also warns that protecting Canadian democratic institutions against foreign interference "will require a shift in the government's perspective and a readiness to take decisive action and impose consequences on the perpetrators."

It added, "Foreign interference will continue until it is seen as an existential threat to Canadian democracy and governments respond strongly and actively."

Vigneault is expected to be asked questions about whether he conveyed the information in the document to senior levels of Trudeau's government.

CSIS's director may also be questioned about the Prime Minister's comments regarding the reliability of the service's work.

Trudeau challenged the CSIS intelligence, according to the investigation.

During his testimony on Wednesday, Trudeau questioned the information collected by the agency, including intelligence suggesting that China may have interfered in the Liberal nomination contest.

The investigation has seen intelligence summaries indicating that CSIS warned that international students were bused in to participate in the nomination vote in the Don Valley North riding, and were given fake documents to allow them to vote for Han Dong – who won the Liberal party nomination, and Chinese officials told them that if they did not participate, their student visas would be at risk and there might be consequences for their families in China.

Trudeau testified that he walked back those allegations, saying, "What worried me more was that the service may not have understood as deeply as political representatives do the extent of the bus loads of various community groups in the nomination campaigns."

Trudeau and other ministers also said they do not feel CSIS intelligence was supported by evidence.

He added, "I did not feel there was enough credible information to justify this very significant step regarding removing the candidate."

During a media briefing on Thursday, one reporter asked Trudeau if Canadians should trust CSIS, in light of his testimony.

The Prime Minister stated that he respects the Canadians working in national security.

He added, "But no government or leader should be merely a passive recipient of information and intelligence."

He continued, "We have a role to play in asking questions and critical thinking... encouraging more work to question sources and pull contradictions. This is in fact an integral part of the work we all need to do to ensure everything is being accomplished, and to keep Canadians safe."

The findings of oversight bodies will be published soon.

This will be Vigneault's third public appearance before the inquiry, having testified last week alongside other security officials and addressing the committee in January when it first began looking into how to conduct a public investigation that deals with confidential information.

After Vigneault's testimony, Commissioner Mary Jose Hog and her team will begin working on their interim report, scheduled to be released on May 3.

This report will not be the only report regarding the credibility of media leaks about foreign interference in elections and the government's response to those reports.

The national security oversight bodies in Canada – the National Security and Intelligence Committee of Parliamentarians (NSICOP) and the National Security and Intelligence Review Agency (NSIRA) – have concluded their investigations into the same issues and submitted their reports to Trudeau.

Revised copies of their findings will eventually be published.