OTTAWA — Canada has expelled six Indian diplomats and consular officials as part of an investigation into the 2023 murder of a Sikh separatist leader in British Columbia, the Department of Foreign Affairs announced October 14.

India earlier said it had ordered the expulsion of six senior Canadian diplomats, including Acting High Commissioner Stewart Wheeler. He added that he had withdrawn his envoy from Canada, contradicting Canada’s statement that it had expelled the envoy.

Relations between the two countries have been strained since 2023, when Canadian Prime Minister Justin Trudeau said he had evidence linking Indian agents to the assassination of a Sikh separatist leader in his country.

The Royal Canadian Mounted Police say they have significant information about extensive criminal activity orchestrated by Indian government agents and used to target members of the South Asian community in Canada.

June 18, 2023: Mr. Hardeep Singh Nijjar, 45, was shot dead in front of a Sikh temple in Surrey, a Vancouver suburb with a large Sikh population. He was a Canadian citizen who campaigned for the creation of an independent Sikh territory carved out of India.

September 1, 2023: A Canadian trade official said Canada had suspended negotiations on a proposed trade treaty with India, an unexpected move that came about three months after the two countries announced plans to strike a first pact in 2023.

September 10, 2023: Indian Prime Minister Narendra Modi expresses serious concerns about Sikh separatist protests in Canada to Prime Minister Trudeau on the sidelines of the Group of 20 summit in New Delhi.

September 18, 2023: Mr. Trudeau told Parliament that Canada was “actively pursuing credible allegations” linking Indian government agents to Mr. Nijjar’s killing.

September 19, 2023: India calls Mr. Trudeau’s assertion “absurd.” Each country expels a diplomat in a tit-for-tat move, with Canada expelling India’s top intelligence officer from the country while India expels its Canadian counterpart.

September 22, 2023: India suspends the issuance of new visas to Canadians and asks Ottawa to reduce its diplomatic presence in India. India resumes issuing visas two months later.

October 19, 2023: Canada has withdrawn 41 diplomats from India over a dispute over Mr. Nijjar’s death, Foreign Affairs Minister Mélanie Joly said.

October 29, 2023: Tens of thousands of Sikhs gathered in Surrey, British Columbia, at the Sikh temple where Mr. Nijjar was killed, to vote in an unofficial referendum on the creation of an independent Sikh state.

November 21, 2023: India’s counterterrorism agency files a complaint against Mr. Gurpatwant Singh Pannun, a Sikh separatist, saying he warned Air India passengers in video messages shared on social media that their lives were in danger.

November 22, 2023: A senior Biden administration official said US authorities had foiled a plot to kill Mr Pannun in the United States and issued a warning to India over concerns that the government in New Delhi was involved .

February 5, 2024: Indian High Commissioner Sanjay Verma said in an interview with Canada’s Globe and Mail newspaper that India would not provide information to Canadian investigators into Mr. Nijjar’s killing until Canada shared the evidence.

April 30, 2024: The White House calls a serious matter a Washington Post report that an Indian intelligence officer was directly involved in both Mr. Nijjar’s killing and the foiled plot to kill Mr. Pannun in the United States .

India’s foreign ministry said the report contained “unwarranted and unsubstantiated imputations.”

May 3, 2024: Canadian police are charging three people in connection with Mr. Nijjar’s murder, according to a source directly familiar with the matter.

August 27, 2024: Canadian police are warning Mr. Pannun, who was an aide to Mr. Nijjar, of an increased threat to his life, a prominent Sikh separatist said. REUTERS