Canadian police on Friday arrested and charged three Indian men with the murder of Sikh separatist leader Hardeep Singh Nijjar last year and said they were investigating whether the men had ties to the Indian government.

Nijjar, 45, was shot dead in June outside a Sikh temple in Surrey, a Vancouver suburb with a large Sikh population. A few months later, Canadian Prime Minister Justin Trudeau cited evidence of Indian government involvement, prompting a diplomatic crisis with New Delhi.

The Royal Canadian Mounted Police named the three men as Karanpreet Singh, 28, Kamalpreet Singh, 22 and Karan Brar, 22.

"We're investigating their ties, if any, to the Indian government," Mandeep Mooker, an RCMP superintendent, told a televised news conference.

Trudeau announced in September that Canadian authorities were pursuing allegations linking Indian government agents to the murder. New Delhi rejected Trudeau's claim as absurd.