Sources cited in the CBC report said investigators had identified the suspects in Canada months ago and had been keeping them under tight surveillance, the CBC said.

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Hardeep Singh Nijjar, a 45-year-old Canadian citizen, was attacked and shot multiple times in while leaving a gurdwara in Surrey in British Columbia on June 18, last year. Canadian Security Intelligence Service had allegedly cautioned Nijjar about potential threats to his life.

Nijjar's killing had sparked a diplomatic row between Canada and India after Canadian Prime Minister Justin Trudeau claimed that Ottawa had credible intelligence linking Indian agents to Nijjar’s killing.

Members of the hit squad are alleged to have played different roles as shooters, drivers and spotters on the day Nijjar was killed at the Guru Nanak Sikh Gurdwara in Surrey, according to the sources cited in the CBC report.

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The men were arrested Friday during police operations in at least two provinces.

CBC report said that sources close to the investigation also told it that police are actively investigating possible links to three additional murders in Canada, including the shooting death of an 11-year-old boy in Edmonton.

Neither the Royal Canadian Mounted Police (RCMP) nor the Indian mission in Ottawa were immediately available for comment.