The Canadian spy agency had information about threats to Air India from Sikh extremists just before the 1985 Kanishka bombing, a former lawyer for the federal government submitted before the Air India inquiry commission.
Graham Pinos said he was told by a senior intelligence officer, just days before the blast, that the service feared Sikh extremists might blow up a plane at some point.
The officer in question was Mel Deschenes, then head of counter-terrorism for the spy service.
When the blast actually occurred, my immediate reaction was, "Holy expletive. They knew," Pinos told the commission.
Michael Anne MacDonald, another lawyer who had dealings with Deschenes at the time, testified that she also felt CSIS had advance information about the bombing that killed 329 people.
Deschenes, now elderly and with a failing memory, is not expected to testify at the inquiry. But in a written statement in 1988, he contradicted the claims of advance warning.
He insisted that, although Sikh terrorism was a serious concern to CSIS, there was no specific intelligence indicating a particular plane would be targeted.