Washington [US], October 16 (ANI): Terming Canada’s allegations “extremely serious,” US has asked India to “cooperate” with Ottawa’s investigation into the killing of Sikh separatist leader Hardeep Singh Nijjar. India and Canada have been dealing with an unprecedented diplomatic crisis after Prime Minister Justin Trudeau alleged that Indian government agents were involved in the killing of Nijjar in Canada. India has rejected Canada’s allegations, terming it “absurd” and “politically motivated.” On Monday, Canada expelled six Indian diplomats and consular officials in connection with a probe o…