A witness in the ongoing Air India bombing inquiry apparently suffered a heart attack just before he was about to testify and other witnesses refused to speak fearing for their lives, said Canadian officials.
The inquiry headed by retired Supreme Court judge John Major hit a major roadblock after one witness was shifted to hospital Wednesday while the rest refused to testify, the Star reported.
Neither Major nor other lawyers involved in the case provided details about the witnesses, or even specified the exact number involved.
In 1985, Air India flight 182 exploded above the Atlantic Ocean, south of Ireland, killing 329 passengers onboard, of whom 82 were children.
The bombing is widely blamed on Sikh separatists who used Canada as a base in their campaign for an independent homeland in India.
Keeping safety concerns in mind, Major proposed to go behind closed doors to hear the testimonies but the plan failed after the witnesses refused to accept the idea.
The retired judge admitted that even if he hears evidence in camera there is a chance the information could eventually be subject to scrutiny by the public through a variety of means.
"We can't assure them of confidentiality," Major said.
"All in all, it leaves the witnesses apprehensive of their safety and that of others if they testify, even at an in-camera hearing. And I can do nothing to assure them that is not the case," he added.
One prime concern of such inquiries relating to terrorism is to offer better protection to witnesses who come forward to testify.
But Major said he simply wasn't in a position to give anyone an ironclad guarantee that their identities will never be revealed if they testify.
"We do live in a democracy where we're governed by the charter, where certain rights are defined and where freedom of the press is enshrined. We live with that and act accordingly," he said.
Last year, Canadian Prime Minister Stephen Harper announced an inquiry, tasked with investigating if Canadian intelligence underestimated the threat posed by Sikh extremists in Canada.