Gardaí have arrested an Irishman as part of an investigation into the alleged bribery of Nigerian officials in relation to an energy deal which gave rise to one of the biggest lawsuits in the world.
The man, who is aged in his 70s and connected to the company Process & Industrial Development (P&ID), is suspected of passing on cash to a Nigerian official to help secure a contract to convert excess gas from the country's oilfields into energy.
The Nigerian government did not proceed with the project and was later sued in a London court by P&ID, in a case which had been backed by a US hedge fund.
In 2017, the court ordered Nigeria to pay €5.8 billion to the company. With interest, this has since grown to €8.75 billion or a quarter of Nigeria's foreign reserves.
It is believed to be one of the largest sums awarded against a government in history. The judgment also gave P&ID the right to seize Nigerian assets abroad and has caused massive political upheaval in the African country.
Nigeria has refused to pay, alleging that the gas deal was corrupt from the start and that the project was planned to fail.
Last year, the UK high court delivered a judgment that said Nigeria had established “a strong prima facie case” that the gas deal was “procured by bribes paid to insiders as part of a larger scheme to defraud Nigeria”.
The judgement outlined allegations that P&ID representatives bribed Nigerian Government officials, including by diverting €17,000 into an official's bank account as a "contribution" to the cost of his son's wedding.
The involvement of the Garda came about as a result of independent inquires by a member of the Garda National Economic Crime Bureau (GNECB) into an Irish-based company which was closely linked to P&ID.
The investigation discovered “what, in our opinion, is potential bribery and corruption”, a senior source told The Irish Times.
GNECB detectives arrested the man, who is aged in his 70s, on Monday morning in south Dublin. He was detained on suspicion of conspiracy, contrary to section 71 of the Criminal Justice Act 2006, a rarely used provision which allows gardaí to investigate offences committed outside the State.
The man was released without charge on Monday night while gardaí prepare a file for the Director of Public Prosecutions (DPP).
"The operation is part of an international investigation in co-operation with Interpol and Nigerian authorities investigating the alleged bribery of Nigerian public officials by Irish nationals," the Garda said in a statement.
P&ID, which is registered in the British Virgin Islands, was founded by Irishmen Brendan Cahill and Michael Quinn.
Both men had a long history of working together before the Nigerian deal, both in Ireland and abroad.
Mr Quinn, who died of cancer in 2015, was a well-known manager of Irish showbands and singers, including Dickie Rock, before becoming involved in military contracting for the Nigerian government.
He had strong political connections in both Ireland and Nigeria and was a witness in the Mahon tribunal, which found large sums of money had been transferred from Mr Quinn's companies to the late politician Liam Lawlor.
At the time, Mr Justice Alan Mahon called Mr Quinn "a singularly unhelpful witness".
Last year the Nigerian government issued an arrest warrant for an Irish citizen linked to P&ID and detained another Irishman who had been working in the country.
The government there has previously said it would seek the extradition of Mr Cahill. It has also requested assistance from Irish authorities and AIB in its investigation of the deal.
Mr Cahill did not return a request for comment on Tuesday but he has previously denied any wrongdoing.