Canadian authorities charge three persons in connection with the killing of Hardeep Singh Nijjar

All three were arrested in and around Edmonton, the capital of the province of British Columbia, They were identified as Karan Brar, 22, Kamalpreet Singh, 22 and Karanpreet Singh, 28. They have been charged with first degree murder and conspiracy to commit murder, according to a release from the Integrated Homicide Investigation Team (IHIT) on Friday.

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However, investigations were continuing for additional persons who were involved in the killing and to establish an Indian link to it. "There are separate and distinct investigations ongoing into these matters, certainly not limited to the involvement of the people arrested today, and these efforts include investigating connections to the Government of India," Commander of the Federal Policing Program in the Pacific Region, Assistant Commissioner David Teboul, said during a press conference in Surrey.

He did not address the nature of the evidence collected or the motive behind the killing because they will come up in the judicial proceedings in the case, expected to begin on Monday after the accused reach Surrey.

"I will say this matter is still very much under active investigation. I will underscore that today's announcements are not a complete account of the investigative work currently underway," Teboul said.

Teboul said investigators were "coordinating and collaborating" with Indian agencies but added that the relationship had become "rather challenging and difficult for the last several years".

The men were taken into custody in Edmonton with the assistance of the Surrey detachment of the Royal Canadian Mounted Police (RCMP) and the Edmonton Police Service.

"The investigation does not end here. We are aware that there could be others out there that played a role in this homicide and we remain dedicated to identifying and arresting each one of them," Superintendent Mandeep Mooker, Officer in Charge of IHIT, said.

All three are believed to have entered Canada in the previous five years as international students and Canadian media reports, citing anonymous law enforcement sources, said they were linked to the Lawrence Bishnoi gang.

Police released images of those arrested and of the Toyota Corolla, believed to have been used by the suspects in the time leading up to the homicide, in and around the Surrey area.

Nijjar's killing caused relations between India and Canada to crater after Canadian Prime Minister Justin Trudeau stated in the House of Commons on September 18 that there were "credible allegations" of a potential link between Indian agents and the murder.

India described that statement as "absurd" and "motivated". Later, Indian officials have reiterated that New Delhi is willing to cooperate with Ottawa if it were to be provided with "specific and relevant information".

Nijjar was the principal organiser in British Columbia of the so-called Khalistan Referendum being held by the secessionist group Sikhs for Justice (SFJ). Reacting to the arrests on Friday, SFJ's general-counsel Gurpatwant Pannun while the action was a "step forward" it "only scratches the surface", as he accused New Delhi and its representatives in Canada of providing "logistical support and intelligence" leading up to the killing.