Canada-based pro-Khalistan leader Hardeep Singh Nijjar was shot dead at the Guru Nanak Sikh Gurdwara in the Punjabi-dominated Surrey city of British Columbia province.
He was the president of Guru Nanak Sikh Gurdwara in Surrey.
Nijjar was associated with the separatist organisation, Sikhs for Justice (SFJ), which is banned in India.
He had played a key role in organising the Khalistan referendum in Brampton city.
The National Investigation Agency had earlier filed a charge sheet against Nijjar for allegedly conspiring to carry out terror attacks.
India had asked Canadian authorities to take action against Nijjar for his alleged involvement in terrorist acts in Punjab.