A man has been arrested as part of a cross-border investigation into money laundering.
Documents were seized in a series of raids on business premises and private homes in Belfast, Wicklow and Dublin, where one man was arrested.
Properties in Bangor, Ballymena, Lisburn, Cumbria and Scotland were also searched.
Police sources said the raids were part of a long inquiry into alleged high level insurance and mortgage fraud.
In Northern Ireland, the Serious Organised Crime Agency and PSNI financial investigators took part.
Detectives in Cumbria and officers from the drug enforcement agency in Scotland and the Criminal Assets Bureau in the Irish Republic were also involved.