The inquiry has already heard that China and other state actors attempted to interfere, but there has been little evidence so far to indicate whether they were successful.
The prime minister told the inquiry one of his longest-serving staffers alerted him on Sept. 30, 2019, in the middle of an election campaign, about the spy agency’s “concerns.”
The public inquiry studying alleged meddling in Canada's most recent elections will hear from the prime minister's national security adviser on Monday.
Former Conservative leader Erin O'Toole is set to testify at a federal inquiry into foreign interference, alongside three politicians who claim China has targeted them.
Canada's chief electoral officer is slated to testify at a commission of inquiry into foreign meddling allegations and how the government responded to them.
He conceded it was difficult to track hidden transactions because Election Canada only has access to overall campaign expenses and not all invoices and justifying documents