The information shared by members of an intelligence-sharing alliance was part of what Canadian Prime Minister Justin Trudeau used to make public accusations about the possible involvement of the Indian government in the assassination of a Canadian separatist leader and Sikh, said the United States ambassador to Canada.

“Intelligence shared between the ‘Five Eyes’ partners helped Canada (make) the Prime Minister’s statements,” US Ambassador David Cohen told Canadian channel CTV News.

CTV News published some of Cohen’s comments Friday evening, and the network said it would air the U.S. envoy’s full interview on Sunday. No further details about the information shared were disclosed.

A Canadian official told The Associated Press on Thursday that the allegation of Indian involvement in the killing was based on surveillance of Indian diplomats in Canada, including intelligence provided by a major ally, without specifying which one.

The “Five Eyes” intelligence-sharing alliance is made up of Australia, Canada, New Zealand, the United Kingdom and the United States.

Relations between Canada and India hit their lowest point in recent history when Trudeau said there were “credible allegations” of Indian involvement in the June killing of Hardeep Singh Nijjar, a separatist 45-year-old Sikh man in a suburb of Vancouver. Both countries have expelled some of their most senior diplomats.

India, which called the allegations “absurd,” also stopped issuing visas to Canadian citizens and asked Canada to reduce its diplomatic staff.

Canada has yet to provide public evidence to support Trudeau’s claims.

Nijjar, an Indian-born plumber who became a Canadian citizen in 2007, had been wanted by India for years before he was shot dead in June outside the temple he led in Surrey, a suburb of Vancouver.