A fourth Indian national has been arrested by Canadian authorities in connection with the killing of Khalistan separatist Hardeep Singh Nijjar in this country, a week after police arrested three Indians linked with the high-profile case that has severely strained India's relations with Canada.

Amardeep Singh, 22, a resident of Brampton, Surrey, and Abbotsford areas of Canada, has been charged with first-degree murder and conspiracy to commit murder.

Nijjar, 45, was killed outside Guru Nanak Sikh Gurdwara in Surrey, British Columbia on June 18, 2023.

The Integrated Homicide Investigation Team (IHIT) of the Royal Canadian Mounted Police (RCMP) said that Singh was arrested on May 11 for his role in the killing of Nijjar. He was already in the custody of the Peel Regional Police for unrelated firearms charges, the release said.

"This arrest shows the nature of our ongoing investigation to hold responsible those that played a role in the homicide of Hardeep Singh Nijjar," said Superintendent Mandeep Mooker, the Officer in Charge of IHIT.  

"IHIT pursued the evidence and gained sufficient information for the British Columbia  Prosecution Service to charge Amandeep Singh with first-degree murder and conspiracy to commit murder," the police statement said.

Investigators said no further details of the arrest can be released due to ongoing investigations and court processes.

IHIT investigators on May 3 arrested three Indian nationals -- Karan Brar (22), Kamalpreet Singh (22) and 28-year-old Karanpreet Singh -- for the murder of Hardeep Singh Nijjar.

All three individuals are Indian nationals living in Edmonton and have been charged with first-degree murder and conspiracy to commit murder.

The ties between India and Canada came under severe strain following Canadian Prime Minister Justin Trudeau's allegations in September last year of the "potential" involvement of Indian agents in the killing of Nijjar.

India has dismissed Trudeau's charges as "absurd" and "motivated."  

Nijjar was a Khalistani separatist and he was wanted in India on various terror charges. -- PTI