IT started in a series of legal letters, the contents of which were definitely never intended for publication.
In late 1994 there was extensive legal correspondence between Ben Dunne and the other members of his family. Ben Dunne was taking proceedings against his siblings following the family split which led to his removal as executive chairman in 1993. As part of the correspondence, he alleged he had paid £1.1 million to former Taoiseach, Mr Charles Haughey.
Following Mr Dunne's departure from the family, a major legal battle started. Mr Dunne issued legal proceedings seeking to break up the family trust which controls the supermarket chain, and claiming it was a sham.
The case was settled shortly after it opened in the High Court, in an agreement under which Mr Dunne is believed to have received around £100 million for his share in the family trust. Effectively, this was his share of the business he had helped to build.
The build up to the court case saw both sides of the Dunne family going to some lengths to prepare evidence against the other. Following Mr Dunne's departure his sister, Mrs Margaret Heffernan, replaced him at the helm. She commissioned accountants Price Waterhouse to examine Mr Dunne's stewardship and payments made by him in his time as executive chairman. It was this document which contained details of the payments to build an extension to Michael Lowry's house.
In response to the Price Waterhouse report, Mr Dunne drew up legal documents which made claims about payments he made as executive chairman. These documents contained allegations against the other members of the Dunnes family; the accountants who were trustees of the family trust were also defendants.
It is in these documents that the allegations about payments to Mr Haughey emerged. The specific details of the payments are contained in legal correspondence between the two parties to the court case. As part of the correspondence, the Dunne family and the trustees sought details from Mr Ben Dunne about his claims.
In response, Mr Dunne alleged, in a document drawn up in late 1994, that four separate payments were made of which Mr Haughey was the ultimate beneficiary. He alleged that:
. in July 1988 a sum of £471,000 sterling was paid from a Swiss account into an account in Barclays Bank in Knightsbridge, payable to a Mr John A. Furze;
. in 1988/89 a sum of £250,000 sterling was paid from Dunnes Stores in Bangor to Mr Furze;
. in May 1989, £150,000 sterling was paid into an account in the Royal Bank of Scotland in Threadneedle Street in London. The account was in the name of another bank, Henry Ansbacher & Co;
. in 1990/91 a further £200,000 sterling was paid from an Isle of Man account into an account in Henry Ansbacher & Co in London.
The total payments come to £1.071 million sterling, or somewhere more than £1.1 million in Irish pounds.
Mr Dunne said he executed three of the four payments and that the other payment - the one which was initiated in Northern Ireland - was undertaken on his instructions by a Dublin accountant, who is named in the documents. The route the money took after the lodgments is unclear.
The John Furze named in the documents is believed to be a Cayman Islands banker. Mr John Andrew Furze helped the late accountant, Mr Des Traynor, set up the Guinness & Mahon operation in the Cayman Islands in the 1970s. Mr Traynor was a partner in the accountancy firm, Haughey Boland and was close to Mr Haughey.
When interviewed by The Irish Times last December, Mr Furze said he was not aware of the payments, or of any money having passed through bank accountants in his name. He said he would not know Mr Dunne "if I tripped over him". The Guinness & Mahon operation in the Cayman Islands was purchased by Henry Ansbacher in 1988. Mr Furze continued to work there until 1995.
It remains to be seen what Mr Haughey's response will be to the allegations. It is also not clear what the tribunal has discovered in its examinations of the transactions mentioned by Mr Dunne. It is understood the original 1994 documents contain precise information, including bank account numbers. Two questions remain.
Firstly, has the tribunal received co operation from the authorities in the bank jurisdictions involved? The tribunal is known to have sought details of bank accounts in the Isle of Man, London and the Cayman Islands.
Secondly, to what extent is it possible to identify the final beneficiary of the payments mentioned? Mr Dunne is thought to allege that a number of intermediaries were involved in the transactions and it remains to be seen how far the tribunal can trace the payments trail. The evidence of one of the alleged intermediaries may also be important.
The tribunal will cast its net wider than the allegation of the £1.1 million payments. It is empowered to look at all payments from Dunnes and its associated companies "within or without the State" received by members of the Oireachtas and their families from 1986.
As such, the tribunal will re examine the transactions involving the former Minister for Transport, Energy and Communications, Mr Michael Lowry. Dunnes Stores paid more than £200,000 to finance Mr Lowry's house extension and the supermarket group said its records showed total payments of £395,000. Mr Lowry has said the payments related to work he and his company - Streamline Enterprises - did for Dunnes Stores. He has disputed Dunnes £395,000 figure.
The Lowry transactions - and all the other transactions examined in the Price Waterhouse report and relevant to members of the Oireachtas - were already examined by Judge Gerard Buchanan. His report said that two thirds of the recipients of the £5.6 million in payments he examined could not be identified because the cheques were made out to cash or bearers, or were paid into credit card accounts.
Fine Gael has said it received some £180,000 in contributions from Mr Dunne, while Labour received £15,000 towards Mary Robinson's presidential election campaign.
The tribunal's wide terms of reference leave the chairman, Mr Justice McCracken, with considerable discretion. Next week will see the first indication of how he will use it.