As first reported by the CBC, the federal government compiled intelligence against Indian diplomats for months following the alleged assassination of a controversial Khalistan supporter in June.
According to government sources that spoke with the state broadcaster, the intelligence includes communications between Indian officials and diplomats on Canadian soil.
Canadian security officials, including National Security and Intelligence Adviser Jody Thomas, went to India in mid-August and earlier this month to seek cooperation on the investigation into the fatal June 18 shooting of Hardeep Singh Nijjar outside a Sikh temple in Surrey, B.C.
The last visit overlapped with the G20 Summit in New Delhi, where Prime Minister Justin Trudeau discussed the matter with Indian Prime Minister Narendra Modi.
"I can assure you that the decision to share these allegations on the floor of the House of Commons […] was not done lightly," Trudeau told the UN General Assembly on September 21.
"It was done with the utmost seriousness.
As of writing, the federal government had yet to release any evidence to substantiate their claims.
Though the Indian government has publicly denied allegations of an extrajudicial assassination on Canadian soil, they did not maintain their denial behind closed-door conversations with Canadian officials, reported the CBC.
Instead, they pivoted to allegations against supporters of Khalistan separatism among Canada's Sikh diaspora, suggesting they influenced the federal government on this matter.
India's External Affairs Ministry claimed Canada has become a safe haven for "terrorists, for extremists and organized crime."
In particular, India has accused Canada of sheltering Khalistanis, including Nijjar, whom it called a terrorist.
India accused Nijjar of conspiring to kill a Hindu priest in Punjab and labelled him a terrorist in 2016 for his alleged involvement in a 2007 Punjab bombing.
Interpol later issued a notice against Nijjar, who they accused of leading the Khalistan Terror Force, followed by a Times of India report that claimed he trained sympathizers to conduct terror attacks in India.
In 2016, Nijjar wrote to Trudeau as a 'peaceful activist,' urging the prime minister to "dispel the Indian government's fabricated, baseless, fictitious and politically motivated allegations against me."
Immigration Minister Marc Miller told Canadians that Nijjar became a Canadian citizen on March 3, 2015, but corrected himself soon after to say he became a citizen on May 25, 2007.
The growing feud between Canada and India has resulted in the expulsion of diplomats from both countries and India placing a temporary bar on Canadian visitor visas.
Trudeau refused questions on whether Canada would retaliate in kind, but government sources told the CBC a decision had not been made yet.
When reporters asked Deputy Prime Minister Chrystia Freeland, she said would not comment on the matter without risking the investigation and Canada's obligations to its Five Eyes partners.
An unnamed Five Eyes ally reportedly helped Canada compile evidence of Indian intelligence networks since the investigation began in June.
"That partnership rests very much on those […] intelligence conversations being held in confidence," she told the state broadcaster.
Freeland said their focus was seeking justice for Nijjar's family and did not speculate whether Canada would pause India visitor visas during the investigation.
"This is not about geopolitics. This is about Canada [and] the safety of Canadians. This is about the rule of law," she said.
The U.S. government did not confirm or deny if it was the Five Eyes ally providing some of the signals intelligence.