The sources claimed that one of those arrested is believed to be Arsh Dalla, who is associated with the banned Khalistan Tiger Force and ran terror modules on behalf of Hardeep Singh Nijjar, a designated terrorist who was killed in June last year.
The official said Sukhvinder's brother Satpal possibly transferred Rs 2.50 lakh from Canada to his cousin Jitu Singh alias Jita in Gwalior to facilitate the November 7 killing.
India on Thursday said it will pursue an extradition request with Canada for Arsh Singh Gill alias Arsh Dalla, the de-facto chief of the Khalistan Tiger Force, following his arrest in that country.
The accused were also allegedly involved in the recent murder of another person in Madhya Pradesh's Gwalior.
The National Investigative Agency (NIA) on Wednesday conducted raids at 51 locations in six states in connection with the crackdown on a terror-gangster network operating in India and Canada, officials said.
The accused have been identified as Rajpreet Singh, Virender Singh, Sachin Bhati, Arpit Dhankar and Susheel Pradhan, the police said.
Gangster Sukhdul Singh alias Sukha Duneke, one of Punjab's most wanted criminals, was killed in the Canadian city of Winnipeg by unidentified people, sources said on Thursday.
At least nine separatist organisations supporting terror groups have their bases in Canada and despite multiple deportation requests Ottawa has taken no action against those involved in heinous crimes, including the killing of popular Punjabi singer Sidhu Moosewala, officials in New Delhi said on Tuesday.
The three have been identified as Parveen Wadhwa alias Prince, Irfan alias Chenu and Jassa Singh.
A terror operative who was the main shooter in the grenade attack on the Punjab police intelligence headquarters in Mohali last year has been arrested from Uttar Pradesh, an official of the National Investigation Agency (NIA) said on Wednesday.
Pro-Khalistan elements based in Canada have been luring gullible Sikh youth to the North American country by sponsoring their visa with the sole objective of using them to carry out their agenda on Canadian soil, sources said on Wednesday.
The NIA had registered three cases last year following information suggesting that terrorist outfits and their sympathisers abroad were operating as members of organised criminal gangs active in the northern states of India for targeted killings and violent criminal acts.
Over the years, Khalistani extremists were further "emboldened" and started "operating with impunity" from Canada.
The Punjab police on Friday claimed to have busted an ISI-backed terror module jointly handled by Canada-based gangster Lakhbir Singh alias Landa and Pakistan-based gangster Harvinder Singh Rinda with the arrest of two of its operatives.