Links between the IRA and the Italian Mafia are revealed in a document opened before an Italian court.
The revelation could have major implications for Sinn Fein and the party's anti-crime stance here.
It comes after an alleged Provisional IRA money launderer was on the run in Africa as Italian police seized €450m in property assets.
The seizure followed a five-year investigation which has uncovered links between the Provisionals and the Mafia.
The alleged money launderer has been named by Italian police as Henry James Fitzsimons (63), who is suspected of forging ties with the Mafia to funnel dirty money from the IRA's criminal activities into holiday developments in the south of Italy.
He is accused of pouring tens of millions into a string of tourist complexes on the stunning Ionian coast of the southern region of Calabria, the heartland of the feared 'Ndrangheta mafia.
Fitzsimons is known to gardai but has not been seen for some time.
He was regularly spotted in the past in the company of Michael McKevitt, the former Provisional IRA quartermaster who defected from the mainstream movement to set up the dissident republican group the Real IRA.
McKevitt is currently serving a 20-year sentence at the maximum security jail at Portlaoise for directing the activities of a terrorist organisation.
Fitzsimons was described by Italian police as "a subject considered by the British authorities to be close to the IRA".
Police said he had "through his ties with organised crime in Calabria, the means to reinvest enormous sums of money in his possession, thanks to the mediation of a noted businessman from Campania".
Situated north of Calabria, Campania is notorious as the home of the Camorra Mafia.
Fitzsimons is one of 20 suspects accused of Mafia association and money laundering and named by Italy's Guardia di Finanza, or finance police.
Sixteen suspects were arrested in dawn raids but the police were unable to locate Fitzsimons and believe he is hiding in an unnamed African country.
The police seized 12 property development companies and 17 to-let holiday complexes, some of them half built, along Calabria's Ionian coast – on the toe of the Italian boot. The property empire is estimated to be worth €450m. Eleven vehicles were also impounded, including four luxury cars.
The money-laundering scam also involved Spanish businessmen in a three-way collaboration between Spain, Italy and the UK.
Searches were carried out in Alicante in southern Spain as part of the operation code-named Metropolis. Two of the Italians named were accused of being leaders of two 'Ndrangheta clans, linked to the Morabito and Aquino families.
Police and judicial investigators say the 'Ndrangheta makes billions of euros a year from drug trafficking, the arms trade and other criminal activities. The arrests and seizures were the result of an investigation, which began in 2008, focussing on the 'Ndrangheta's investments in tourism and property in the far south of Italy.
Police said members of the Calabrian mafia and Spanish businessmen had created a "joint venture" to build residential and tourism properties, starting in 2005.
Through "the force of Mafia intimidation", they had managed to obtain and develop the land "through a complex network of Italian and foreign companies." The investigation was led by Nicola Gratteri, a veteran anti-mafia prosecutor based in the southern port city of Reggio Calabria.
"The 'Ndrangheta has shown its criminal capacity to spread well beyond its home territory," he said.
The prosecutor described Fitzsimons as "a middle-man delegated by the IRA to recycle the proceeds of terrorist activities and to reinvest the financial resources of the movement."
A police statement said: "This is a new 'Ndrangheta entrepreneurship, a new way of carrying out Mafia activities. What emerges from the investigation is an international and modern 'Ndrangheta, with a complex structure and a colonising and expansionist philosophy."