Amandeep Singh, 22, was already in custody for unrelated firearms charges when he was charged with the murder of Hardeep Singh Nijjar.

The 45-year-old Canadian Sikh was shot dead in the parking lot of a Sikh temple in Surrey, British Columbia, where he was president last year.

In a statement released late on Saturday, British Columbia's Integrated Homicide Investigation Team said it "gained sufficient information for the BC Prosecution Service to charge Amandeep Singh with first degree murder and conspiracy to commit murder".

Read more: India and Canada relations at their lowest ever in wake of killing

Amandeep Singh - an Indian national who spent time in Brampton, Ontario, as well as Surrey and Abbotsford in British Columbia - is the latest man arrested over the killing of Mr Nijjar.

Police arrested Karan Brar, Kamalpreet Singh and Karanpreet Singh - all also Indian nationals - in Edmonton earlier this month.

All three were charged with first degree murder and conspiracy to commit murder.

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Mr Nijjar, an Indian-born citizen of Canada, was a leader within the Khalistan movement - a group calling for the creation of an independent Sikh homeland.

He was organising an unofficial referendum in India for an independent Sikh nation at the time of this death and had denied allegations of ties to terrorism.

The killing led to Canadian Prime Minister Justin Trudeau sparking a diplomatic feud with India, with him claiming in September there were "credible allegations" of Indian involvement in the killing.

India denied involvement and since then has told Canada to remove 41 of its 62 diplomats in the country.