Gardai investigating violence against Quinn Industrial Holdings (QIH) have uncovered a network of front companies and bank accounts used to launder monies paid to senior criminal Cyril McGuinness.
Millions of euro were funnelled through the bank accounts of up to five bogus companies, it has been learned.
They were registered in the Republic and ostensibly set up to buy and sell plant machinery.
Security sources revealed that the money trail may finally uncover evidence of direct links between McGuinness - dubbed 'Dublin Jimmy' - and the paymaster suspected of bankrolling the vendetta against the companies formerly owned by Sean Quinn.
A campaign of violence and intimidation against QIH executives culminated in the abduction and torture of Kevin Lunney last September. The chief operations officer for QIH was beaten and tortured in a horse box.
He was left severely injured and traumatised before being dumped on a remote roadside in Co Cavan.
The Garda National Economic Crime Bureau, CAB and the National Bureau of Criminal Investigation are involved in a complex investigation to trace McGuinness's wealth and the monies he was paid for carrying out the attacks.
The enquiry has been focusing on a series of companies which were set up to launder the proceeds of crime by an accountant operating from Co Galway.
At least one of the companies is registered in Co Sligo in the name of a man who suffers from alcohol-related problems and, it is understood, was unaware he was the registered owner of the company. It is understood that €970,000 was washed through the company's bank accounts.
Gardai have established that McGuinness withdrew over €500,000 in cash through ATM machines in counties along the Border two years ago.
Detectives are now trying to establish proof that the accounts were used by a relative of the paymaster to funnel cash to McGuinness. This would have been done as payment for arson attacks and other acts of violence, which included the abduction and torture of Mr Lunney.
Gardai have received intelligence reports that associates of McGuinness bought farms as part of the money laundering operation. A London-based construction company and a large UK property portfolio, which is owned by one of his closest associates from Co Cavan, is also being investigated.
'Dublin Jimmy' died from heart failure last November when police raided his safe house in Derbyshire.
At the time, UK police seized phones and computers which, it was hoped, would uncover evidence of the criminal's business arrangements with the paymaster.
However, sources have revealed gardai have only been given access to a limited portion of the material recovered from McGuinness's devices.
It sparked speculation in some quarters that efforts are being made to cover up the fact McGuinness was working as an agent for some UK security services.
Security sources have confirmed that McGuinness worked with the IRA for several years and was particularly close to IRA godfather Thomas 'Slab' Murphy.
The 'work' involved providing transport for bombs and smuggling operations, according to one former senior Special Branch source.
Meanwhile, it emerged this week that gardai have officially informed the directors of QIH that the threat level against each of them is as "high as it has ever been".
The revelation followed an apparent resumption of violence against QIH when an attempted arson attack took place at the home of a relative of one of the directors last weekend.
The incident occurred in the early hours of last Saturday morning near Derrylin, when two men tried to set fire to a truck and another vehicle which were parked near the relative's home. However, it is understood that the would-be arsonists were disturbed and sped off before any damage was done and the incident was captured on CCTV.