One man was arrested today as part of a massive investigation into money laundering on both sides of the border.
The PSNI, British police and gardaí belonging to the Criminal Assets Bureau were involved in the search.
Documents were seized in a series of raids on business premises and private homes in Belfast, Wicklow and Dublin, where one man was detained.
There were searches as well in Ballymena and Lisburn in Co Antrim, and Bangor in Co Down.
A PSNI spokesperson said the operation was part of a protracted investigation which had been ongoing for 'several months'.