VANCOUVER, B.C. - Twenty-five years after Air India Flight 182 fell from the sky off the coast of Ireland, the legal saga stemming from Canada's worst mass murder continues this week as a key witness in the trial of two men acquitted in the bombing is tried for perjury.

Inderjit Singh Reyat is charged with lying in 2003 during the trial of Ripudaman Singh Malik and Ajaib Singh Bagri. Malik and Bagri were acquitted of all charges connected with the 1985 bombing of the Air India plane and another explosion at a Tokyo airport.

Reyat was called as a Crown witness at the trial, but the indictment for his perjury charge lists 27 instances in which he is alleged to have lied under oath, mostly dealing with his insistence that he didn't remember details of the bombing plot or the name of one of the men involved.

Reyat, an electrician from Duncan, B.C., was charged with perjury in February 2006, nearly a year after the acquittals.

His trial has been delayed several times as lawyers prepared for the case, but jury selection last week set the stage for hearings to begin in a Vancouver courtroom on Monday.

The Crown's theory during the trial for Malik and Bagri was that Sikh extremists in British Columbia, angered by the Indian government's June 1984 attack on the Golden Temple in Amritsar, Sikhism's holiest shrine, plotted to bring down Air India planes. A bomb planted in a suitcase blew up Flight 182, killing 329 passengers and crew, and another killed two baggage handlers in Japan.

The alleged mastermind behind the attacks, Talwinder Singh Parmar, was killed by police in India in 1992. Parmar was the leader of Babbar Khalsa, which the Canadian government considers a terrorist organization.

Reyat's perjury indictment, which was read to all prospective jurors last week, outlines the specific occasions when prosecutors allege the man lied during testimony in September 2003.

Among them:

-Reyat said he did not know if Parmar was the leader or played any role in Babbar Khalsa, and did not know the purpose of the organization.

-He testified that when Parmar asked him to make an explosive device, Parmar did not describe "in detail" what the device would be used for.

-Reyat said he did not know the identify of one of Parmar's associates, known only as Mr. X, despite meeting the man on several occasions and allowing the mystery man to stay at his home.

-He told the trial that he never asked Parmar or Mr. X whether the explosive device he helped with had ever been built or how it may have been used.

-Reyat testified he told either Parmar or Mr. X he did not want to build a device if people would get hurt and they assured him that wouldn't happen. But when "it became clear his components had been used to kill people," Reyat testified that he never asked Parmar or Mr. X about it.

The perjury trial, which is expected to last as long as two weeks, will be heard by a jury of eight women and four men.

None of the allegations against Reyat have been proven in court.

Neither the Crown attorney prosecuting the case nor Reyat's lawyer could be reached for comment.

Vancouver criminal lawyer Greg DelBigio, speaking in general terms about the offence of perjury, said the Crown must prove three things to obtain a conviction.

"There has to be (evidence) that somebody said something that was in fact false, that the person who said it knew it was false, and that there's an intent to mislead," said DelBigio, noting that perjury cases are rare.

"For example, a mistake is not good enough, an unintentional error is not good enough. The other thing is that a person can genuinely believe something to be true when it is, in fact, false, so that's not good enough, either."

He said in some cases, proving all of those things can be a challenge.

"I guess one difficulty is, how do you prove that someone said something that he or she knew to be false?" he said.

"It might be easy enough to prove that somebody made a mistake by simply showing that the fact testified to is wrong, but how do you prove that the person knew the truth and intended to testify falsely?"

Perjury carries a maximum penalty of 14 years in prison, although maximum sentences are rarely imposed.