Justin Trudeau accuses foreign powers, including India, of involvement in Hardeep Singh Nijjar's killing.
Indian Ministry of External Affairs calls Trudeau's claims "absurd" and "motivated."
Canada expels a senior Indian diplomat in response to the allegations.
Hardeep Singh Nijjar, a Canadian citizen, was the leader of the Khalistan Tiger Force.
ijjar was shot outside a gurdwara parking lot in Surrey, British Columbia, on June 18.
Trudeau emphasizes the violation of Canada's sovereignty if a foreign government is involved in a citizen's killing.
Canadian security agencies investigate potential links between India and Nijjar's killing.