The Canadian government has opened a public inquiry into the 1985 bombing of an Air India flight that killed all 329 people off the Irish coast.
No one has ever been convicted in the attacks, although one man pleaded guilty to a peripheral role in a second bombing at Tokyo's Narita airport and was sentenced to five years in prison.
Canadian prime minister Stephen Harper told parliament that he hoped an inquiry into the bombings would ease the pain of victims' families and give Canadians a better sense of security.
"This inquiry is not a matter of reprisal, nor is it intended to go back over the criminal trial. That would serve no purpose," he said.
Instead, he said, the inquiry would try to find answers to "several key questions that have emerged over the past 20 years about the worst mass murder in Canadian history."
Air India Flight 182 from Montreal to London, originating in Vancouver, exploded and crashed 100 miles off the Irish coast
on June 23rd, 1985. An hour earlier, a bomb in baggage intended for another Air India flight exploded in the Tokyo airport, killing two baggage handlers.
A total of 131 bodies were recovered 100 miles off Cork.
Before the bombings, Canadian intelligence officials had apparently learned of a plot by Sikh separatists in Canada and India to launch a terrorist attack. Hours of secretly taped conversations between Sikh separatists in Canada and their counterparts in India was erased by intelligence officials, though whether it was accidental is still unclear.
Prosecutors maintained the bombings were the work of Sikh radicals, seeking revenge for a deadly 1984 raid by Indian forces on the Golden Temple in Amritsar, the holiest site of their religion. About 800 Sikhs, including militants taking refuge in the temple, died.