The 1985 Kanishka bombing was the result of an intelligence failure of massive proportions, a former senior intelligence official said.
"I've always carried the view that this is the biggest and most disastrous civil intelligence failure that Canada has faced," Henry Jensen, former deputy commissioner of operations, Royal Canadian Mounted Police (RCMP) told the inquiry panel probing the bombing of the Air India plane on Monday.
He blamed the then Canadian government's decision to abolish the old RCMP security service and replace it with the Canadian Security Intelligence Service (CSIS) as one of the prime reasons behind the intelligence collapse.
"The reform left an enormous gap in the RCMP's ability to detect terrorist plots and head them off before they could come to fruition. We didn't have the resources to do it. We were gutted. I attribute this to a naiveté of parliamentarians and government," he said.
According to documents tabled before the inquiry panel last month, Canadian security officials were warned by Air India about bomb threats, but they played it down by saying the airline was simply "crying wolf" to get extra security at no additional cost.
Critics have long blamed turf battles between the RCMP and CSIS for the failure to avert the bombing, and for hampering the criminal investigation that followed the attack, the Star reported.
Air India Flight 182 exploded while at an altitude of 31,000 feet above the Atlantic Ocean, south of Ireland, killing 329 passengers onboard, of whom 82 were children.
Until September 11, 2001, the Kanishka bombing was the single deadliest terrorist attack involving aircraft. It is also the largest mass murder in Canadian history.
Last year, Canadian Prime Minister Stephen Harper announced an inquiry, tasked with investigating if authorities underestimated the threat posed by Sikh extremists in Canada and if security agencies in Canada impeded the prosecution and appointed former Supreme Court justice John Major to head the inquiry.