By Stephen Mulvey
The acquittal of two men accused of involvement in the bombing of an Air India jet is the climax of a 20-year investigation that has been dogged by controversy from the start.
Ripudaman Singh Malik and Ajaib Singh Bagri denied involvement
The trouble began even before the bombing took place on 23 June 1985.
On 4 June, members of the Canadian secret services followed two men to some woods on Vancouver Island.
They heard a loud explosion, but did not regard the incident as important.
Five months later the two men, Talwinder Singh Parmar and Inderjit Singh Reyat, were arrested on various weapons, explosives and conspiracy charges.
Police revealed that the charges were connected with the Air India disaster.
However, the case against Parmar turned out to be flimsy, and charges were dropped.
Reyat was fined on a minor explosives charge.
Parmar, regarded by the Royal Canadian Mounted Police (RCMP) as the mastermind of the Air India bombing, was killed by police in India in 1992.
Reyat ultimately pleaded guilty to manslaughter in connection with the Air India bombing.
He was sentenced to only five years in prison, but widespread expectations that he would testify against Ripudaman Singh Malik and Ajaib Singh Bagri, who have now been acquitted, proved unfounded.
After charges against Parmar were dropped in 1985, the next embarrassment for the investigation came with the news that the Canadian secret services (CSIS) had destroyed tapes of telephone calls made by Sikhs suspected of involvement in the Air India case.
DEAD, JAILED AND ACQUITTED
Talwinder Singh Parmar - the mastermind. He was killed by police in India in 1992
Inderjit Singh Reyat - admitted assisting with the construction of the bomb, but denied knowing its intended target. Jailed for five years in 2003
Ripudaman Singh Malik - acquitted of financing the bomb plot
Ajaib Singh Bagri - acquitted of transporting the bomb to Vancouver airport
In his verdict this week, the judge in the trial described this as "unacceptable negligence" but members of parliament who have called for an inquiry regard it as far more serious than that.
In 2000 a former secret services officer told the Toronto Globe and Mail newspaper he had destroyed the 150 hours of tapes rather than hand them over to the Mounties, because he feared the identity of informants would be revealed.
And according to RCMP documents, the CSIS ordered the destruction of the wiretaps to conceal the fact that one of its agents had infiltrated a circle of Sikh extremists planning the attack.
He was ordered to pull out three days before Air India Flight 182 blew up.
The next blow for investigators came in November 1998, when a Sikh publisher, Tara Singh Hayer, was killed at his home.
Mr Hayer was to have been a prosecution witness in the Air India trial, and had already been paralysed in an earlier attempt on his life.
The case presented against Mr Malik and Mr Singh in court, after an investigation costing $45m, turned on the reliability of key prosecution witnesses, who claimed the accused had privately confessed to involvement in the bombing.
One was a woman who had been employed by Mr Malik.
The pair had been close, but Mr Malik later fired the woman (given anonymity by the court) after reportedly calling her a "slut".
The judge concluded that she had "not been truthful" with the court, saying he found it hard to believe her when she said that she still loved and respected Mr Malik, despite testifying against him.
Another witness, an FBI informant from New York referred to as "John", was controversially paid $460,000 to testify against Mr Bagri.
He said he needed the money to protect himself and his family against possible retaliation.
Another witness who came forward with evidence implicating Mr Malik at a very late stage, after the trial had started, admitted that he was in serious financial difficulties, but denied that the hope of collecting a reward had inspired him to give evidence.