Three people were charged in the killing of a Sikh leader in British Columbia, which Prime Minister Justin Trudeau accused India of orchestrating, fraying relations between the two countries.

Hardeep Singh Nijjar, a Sikh nationalist and Canadian citizen, was gunned down last June by two masked assailants in the parking lot of the temple in Surrey, British Columbia, where he was president, according to the police.

Three men, all Indian nationals in their 20s, were all arrested in Edmonton, Alberta and charged with first-degree murder and conspiracy to commit murder.

Mr. Nijjar was a leader in the local Khalistan movement, which seeks to create a separate Sikh nation in India that includes the northern state of Punjab.

Mr. Nijjar was born in Punjab and moved to Canada in the heat of India’s crackdown on Sikh leaders in the 1990s, according to Indian media reports. He was the leader of the Guru Nanak Sikh Gurdwara temple in Surrey, a city outside Vancouver that is home to one of the largest Sikh populations in Canada.

The Indian government had labeled Mr. Nijjar a terrorist in 2020, and called for his arrest.

His killing set off diplomatic skirmishes between Canada and India, after Mr. Trudeau accused India of being involved in the killing on Canadian soil. The Indian government strongly denied the accusation, which led both countries to expel senior diplomats.