A suspect has been arrested in Co Louth as part of an investigation into alleged money-laundering of €29m.
It's believed a crime gang in the border region is transferring large sums of money to bank accounts overseas in a VAT fraud operation.
In September 2016, gardaí started a multi-agency investigation into a multi-million euro VAT carousel fraud.
VAT carousels involve more than one jurisdiction and multiple suppliers.
Funds were identified moving through bank accounts linked to companies either side of the border, under the control of an organised crime gang.
A woman and a man had previously been arrested, in May and August respectively.
Yesterday, another suspect was taken to Dundalk Garda Station but was released without charge.
A file is being prepared for the DPP and investigations are ongoing.