Canada has urged India to cooperate in an investigation into the murder of Sikh separatist leader Hardeep Singh Nijjar, Reuters reported on Thursday.

On September 18, Canadian Prime Minister Justin Trudeau told the country’s Parliament that intelligence agencies were actively pursuing “credible allegations” tying agents of the Indian government to Nijjar’s killing. He was killed by masked gunmen on June 18 near Vancouver.

Nijjar was a supporter of Khalistan, an independent Sikh nation sought by some groups. He was the head of the Khalistan Tiger Force, which is designated a terrorist outfit in India. India rejected Trudeau’s allegations as “absurd and motivated”. Later, India’s External Affairs Minister S Jaishankar said he had informed Canada that it was not New Delhi’s “policy” to engage in such acts.

Trudeau’s request for cooperation on Wednesday came hours after the US Attorney’s Office, Southern District of New York, filed “murder-for-hire charges” against an Indian national named Nikhil Gupta in connection with his alleged participation in a thwarted plot to assassinate Gurpatwant Singh Pannun, a Sikh separatist leader in New York City.

“The news coming out of the United States further underscores what we’ve been talking about from the very beginning, which is that India needs to take this seriously,” Trudeau told reporters in Ottawa. “The Indian government needs to work with us to ensure that we’re getting to the bottom of this.”

Gupta had told a US undercover agent that Nijjar “was also the target,” according to the US Attorney’s Office.

Canadian Foreign Minister Melanie Joly too sought more cooperation and more engagement from the Indian government on the matter.

Canada is yet to charge anyone in Nijjar’s murder, the Reuters report added.

‘Allow return of diplomats’

Meanwhile, Joly urged the Indian government on Thursday to allow the return of 41 diplomats that had left India in the wake of tensions between India and Canada, The Indian Express reported.

“It is my hope that the 41 diplomats, who should be working right now in India, are allowed back,” the report quoted her saying at a news conference in Brussels, the capital of Belgium.

On October 19, Joly had said that her government has withdrawn 41 of its 62 diplomats from India after the Modi government allegedly threatened to unilaterally revoke the diplomats’ official status.

Joly had said that Canada would not take the retaliatory step of asking India to withdraw its diplomats.

She had termed India’s demand “unreasonable and escalatory” and claimed that New Delhi revoking the diplomats’ official status violated the Vienna Convention on Diplomatic Relations, the cornerstone of international relations and international law.

After the move, the number of Canadian dimplomats in the country was reduced to 21.