It has taken nearly 18 years for Canada to bring the so called two main suspects involved in the Air India disaster to trial.

In a $4.8 million Vancouver basement courtroom specially constructed for the case, the alleged conspiracy by Ajaib Singh Bagri, 53, and Ripudaman Singh Malik, 56, is being played out after the two pleaded not guilty to charges relating to the worst terrorist bombing of a commercial aircraft.

The prosecution team described the trial as the final chapter of a tragic incident - the result of one conspiracy fuelled by revenge for the attack on Sikhdom's holiest shrine.

But what is beginning to emanate from the high-tech courtroom is not only a militant plot.

The trial is expected to display the unprecedented bungling by Canadian spies and police investigators, sordid deals made between the crown and witnesses and payouts to journalists.

Many feel that the cocktail of cockups is lethal enough for the defence to torpedo the C$100 million dollar investigation and allow the suspects to walk or cut a plea for time served.

If you, like the anguished familes of the victims of Air India are expecting justice in this trial, be prepared for the worst as this complicated case has thrown up many surprises in the past and promises to do so in the future.

Air India flight 182 disappeared from radar screens in late June of 1985.

All 329 people on board--mostly Canadians of Indian origin--died.

The attack has been blamed on Sikh separatist militants fighting from a base in Canada for an independent homeland in Indian Punjab.

Right from the start, the investigation was mired in controversy.

The Canadian spy agency and RCMP did not have any expertise in the field of Sikh militancy in Canada. They began relying heavily on journalists like the Province's Salim Jiwa, the Vancouver Sun's Kim Bolan and Punjabi radio host Sukhminder Cheema.

Jiwa, Bolan and Cheema played critical and controversial roles with their sources assisting investigators while trying to outdo each other.

Cheema, for instance, was paid more than $100,000 by the RCMP over a number of years while he was agreeing to be a witness.

The RCMP also assisted Cheema in getting landed status in Canada despite him having a criminal record. Efforts by the police to get Cheema Canadian citizenship were unsuccessful.

Cheema now has refused to testify because he fears for his safety. Sources say he was taken to a garage in Surrey and "given some advice".

Jiwa's book on the tragedy and Bolan's relationship with a key witness, once spurned by Malik, is also to take centre stage as the trial continues.

The defence wants to know how police statements ended up in Jiwa's book verbatim and whether this was part of a quid pro quo arrangement.

Another key factor of the case will be the destruction of surveillance tapes by the Canadian spy agency, which otherwise would have bolstered the prosecution's theory.

The crown was also taken by surprise when it was told that one of it's principal witnesses, whose identity has been banned by the court, is a killer from India.

The man, who faces deportation from the U.S. was paid over $300,000 and is expected to testify that Bagri admitted in September 1985 that "he was responsible."

The identify of the main witness against Malik (Bolan's source) has also been cloaked by court order.

She will testify that Malik told her, "We had Air India crash," and "It is all for Sikhism. I am like a Hindu god."

But those familiar with the inner workings of this investigation know that this witness has a long standing grudge against Malik and had been calling the media to write negative articles about him and his Khalsa School.

The defence has described the woman as a disgruntled ex-employee who was so bitter that she filed a human rights complaint, as well as a civil suit against Malik.

Yet another witness is a Lower Mainland woman who gave statements to investigators about Bagri wanting to borrow her car to take baggage to the airport. She has recanted the information. The woman who has undergone psychiatric evaluations now claims investigators harassed her into making 13 different statements. She is also refusing to meet with crown or police.

The Air India trial is supposed to close a tragic chapter in Canadian history.

What it has done so far is open a can of worms.