Graham turned over phone records to police investigating €1.6bn deal
Businessman Gareth Graham became a key figure in the Project Eagle controversy when he handed police thousands of hours of phone recordings involving former Nama adviser Frank Cushnahan.
He also travelled to the US, where he complained about aspects of the deal to the Securities and Exchange Commission.
The Belfast-based property developer and bookmaker gave sensational evidence last September at the Stormont inquiry into the sale of the Nama portfolio.
He said he had recordings involving Mr Cushnahan which demonstrated "an ingrained culture of inappropriate and quite possibly illegal business conduct".
This stretched "across political, legal, banking and accountancy sectors", he said.
The allegations came against the backdrop of a bitter court battle between Mr Graham and US vulture fund Cerberus, which was seeking to appoint administrators to a number of his companies.
Mr Graham was one of 55 Nama debtors whose loans were sold to Cerberus for €1.6bn as part of the Project Eagle deal in April 2014.
But, unlike many other developers, he had not been able to reach a deal with the vulture fund on his debts. This perplexed Mr Graham, who insisted the companies were financially strong and had never missed a payment.
In the ensuing legal battle, his lawyers argued that if any third parties received "fixers" payments in relation to the Project Eagle sale, the deal would be rendered illegal.
Following the news last night that an agreement has finally been reached with Cerberus, Mr Graham now says he is content that the fund is not and was not involved in any illegal conduct.
Frank Cushnahan has denied he was to receive a "fixers" payment, but appeared to say the opposite in a secretly recorded conversation broadcast by the BBC.
He and Mr Graham were once close business associates. However, the relationship turned sour three years later.
While Mr Graham has now distanced himself from allegations against Cerberus he reserved his position "in relation to other entities connected to Project Eagle".