Garda inquiries into the "money trail" from sham marriages played a major role in the seizure of 85 cars valued at more than €2m.
The raid by the Criminal Assets Bureau (CAB) at a used-car dealership was one of six carried out in Tipperary and Clare yesterday as part of an investigation into an international crime gang.
Gardaí also seized two trucks and a car transporter.
As gardaí pounced on four homes and two businesses, police in the West Midlands, England, arrested four people for 'invoice redirect' fraud offences targeting companies in the UK. They seized 90 cars of a similar quality to those taken by CAB.
Last night, a senior source told The Herald the gang at the centre of the investigation has made millions from sham marriages here.
It has been a main target for the Garda National Immigration Bureau (GNIB) as part of Operation Vantage, which was launched in 2015.
"Intelligence from the GNIB investigation as well as information from the West Midlands Police enabled the CAB to seize the vehicles under proceeds of crime legislation," a senior source said.
Operation Vantage was established to investigate sham marriages involving an EU citizen marrying someone from outside the EU so that person could secure immigration status.
Men from Pakistan, India and other Asian countries paid around €20,000 each to marry women from EU countries, mostly in eastern Europe, with the women being each paid on average less than €2,000 for their role.
"It was a huge money-making operation but gardaí have effectively shut the sham marriages down over the last number of years but the gang still needed to launder money they got from it," the source explained.
"That is where this car dealership came into it - the cars were bought legitimately in the UK with money that was the proceeds of crime and then brought to the dealership in Co Tipperary where the cars were registered here and sold.
"The front business was actually thriving in recent months and even while the garda raids were going on a number of potential customers arrived to inspect or buy cars. They had to be turned away while the search continued at the premises," the source explained.
Inspections by specialist detectives from the garda's stolen motor vehicle investigation unit established that none of the 85 cars here had been stolen.
"This is a major international crime gang who are now involved in serious organised fraud in the UK and they have been using the business to launder money," the source added.
Among the 85 cars seized here were high-end models such as Range Rovers and BMWs.
The Criminal Assets Bureau also confiscated more than €21,000 in cash and froze in excess of €200,000 in bank accounts here. Gardaí have made no arrests.
Detective Chief Superintendent Michael Gubbins said the operation "is an example of the cooperation between the Criminal Assets Bureau, An Garda Síochána and UK police forces in the investigation of international organised criminal groups. Our activities are in furtherance of the CAB mission to deny and deprive".