VANCOUVER, Canada, May 12: In a significant development, Canadian authorities have apprehended and charged a fourth Indian national in connection with the killing of a separatist Sikh activist in Vancouver last year. The case, which has strained diplomatic relations with India, continues to draw attention.

Amandeep Singh, 22, already in custody on unrelated gun charges, now faces charges of "first-degree murder and conspiracy to commit murder" in the slaying of Hardeep Singh Nijjar, according to the Integrated Homicide Investigation Team (IHIT) statement issued on Saturday.

Singh, who resided in Brampton, Surrey, and Abbotsford, becomes the latest individual implicated in the case. Earlier this month, three other Indian nationals were arrested in Edmonton, Alberta, with authorities probing potential ties to the Indian government. Kamalpreet Singh, 22; Karan Brar, 22; and Karanpreet Singh, 28, appeared in court on Tuesday via videolink, consenting to an English trial. They face similar charges of first-degree murder and conspiracy to commit murder.

While Sikh leaders in North America have welcomed the arrests, concerns regarding the alleged involvement of the Indian government have persisted, fueling unease and raising questions about international relations dynamics.

Hardeep Singh Nijjar, 45, was fatally shot outside a Sikh temple in Surrey last June. Nijjar, an advocate for Khalistan, an independent Sikh homeland, faced opposition from the Indian government, which had labeled him a "terrorist."

Canadian Prime Minister Justin Trudeau's remarks hinting at potential Indian government involvement in Nijjar's murder had triggered diplomatic tensions, resulting in a temporary visa curb for Canadians by India and the withdrawal of diplomats by Ottawa.

In a related development, the US Department of Justice recently charged Indian citizen Nikhil Gupta, residing in the Czech Republic, with plotting an assassination attempt on US soil against Sikh-American activist Gurpatwant Singh Pannun. Allegations of Indian government involvement in this case have also surfaced, indicating complex international implications.

As investigations continue, the case underscores the delicate balance in international relations, particularly concerning issues of sovereignty, security, and diaspora activism.