More than 300 people were killed when the Air India jumbo, en route from Montreal to Delhi, exploded off the coast of Ireland on 23 June 1985.

I destroyed the tapes and the sources were cut lose

Former Canadian agent

Investigators established that a bomb caused the crash but closed the case without filing any charges.

The Canadian intelligence service has asked the Royal Canadian Mounted Police to investigate the claim.

Startling revelation

The agent - whose identity has not been revealed - told Canada's Globe and Mail newspaper that he destroyed taped interviews with two people who had been questioned during the investigation.

If their identity had become known...they would have been killed. There is no doubt in my mind about that

Former Canadian agent

The agent said the two men - who were from Canada's Sikh community - wanted to remain anonymous, and he feared their request would not be honoured if the tapes were handed over to the police.

"I destroyed the tapes and the sources were cut loose," he said.

"I told them [the sources] I was no longer able to protect their identities," he said.

"If their identity had become known in the Sikh community, they would have been killed. There is no doubt in my mind about that," the agent said.

The attack was believed to have carried out by Sikh extremists to avenge an attack by Indian troops on the Sikh holy shrine, the Golden Temple, in 1984.

Turf battle

The agent said the investigation had been so badly bungled that there was a near mutiny by investigators handling the probe.

I felt sick when I heard about this. It brought it all back to me like it had just happened

Victims's relative Sushila Rauthan

He said it led to a fierce turf war between the Canadian intelligence agency and the Mounted Police.

But a Mounties spokesman said the two agencies had a good working relationship.

"I just find it difficult to accept on face value that 14 or 15 years later somebody comes out of the blue and says 'I just want to set the record straight'," Corporal Grant Learned said.

Families of the victims reacted bitterly to the latest twist, the Globe and Mail reported.

"I felt sick when I heard about this. It brought it all back to me like it [the bombing] had just happened," said Sushila Rauthan, an Ottawa woman whose husband and teenaged daughter died in the bombing.