Two B.C. men have pleaded not guilty to eight charges, including first-degree murder, attempted murder and conspiracy, in the 1985 bombing of Air India Flight 182, which killed 329 people on board.

The trial of Ripudaman Singh Malik and Ajaib Singh Bagri began on Monday in Vancouver, nearly 18 years after the flight exploded off the coast of Ireland.

The trial follows the longest and most expensive police investigation in Canadian history. It is expected to last at least a year, during which time the court is expected to hear testimony from 150 witnesses.

Ripudaman Singh Malik and Ajaib Singh Bagri listen to opening arguments at the Air India trial (CP PHOTO)

The prosecution's case hinges on the testimony of two witnesses that cannot be identified.

One of the witnesses claims that back in 1986, Malik bragged about his role in the bombing, saying "We had Air India crash. It is all for Sikhism."

According to the witness, Malik confessed that he made arrangements to have someone take a suitcase, with a bomb inside, to the airport.

The defence says the prosecution's case against the two men is flimsy at best. One of the witnesses had a grudge to settle, the defence says, and the other was paid $300,000 for his testimony.

Bagri, a 53-year-old sawmill worker from Kamloops, B.C., and Malik, a 56-year-old Vancouver millionaire, sat side by side in the new high-security courtroom built for the trial.

A third man, Inderjit Singh Reyat, pleaded guilty to manslaughter this year and was sentenced to five years in prison. He had served 15 years in prison for his part in a bombing at Tokyo's Narita Airport.

Crown attorney Robert Wright opened the prosecution case with the news that Reyat will testify against Malik and Bagri.

As a precaution, an area the size of a city block was sealed off from traffic, and spectators entering the courtroom went through security checks an hour and a half before the trial began.

A satellite courtroom was set up in a separate building where members of the media and the public can watch the trial on closed circuit TV.

The men are accused of conspiring to plant two bombs, one that destroyed Flight 182, and another that killed two baggage handlers when it exploded at Narita airport on the same day in June 1985.

All 329 people on board the 747 were killed when it exploded over the Atlantic and plunged into the ocean.

Police say the bombings were planned as part of violent struggle by Sikhs for independence from India.

The Crown and defence teams have reportedly been working out a last-minute deal that, if accepted by the court, would shorten the trial, perhaps to less than a year.

That the case took so long to come to trial has been blamed in part on bungling by the RCMP and CSIS, Canada's spy agency.

The investigation has also been marred by allegations of witness tampering. Two prospective witnesses have been killed.