Offices were searched in Armagh and Antrim as part of a probe into a major fraud which
involved investors on both sides of the border being swindled out of as much as £4 million sterling.
Raids were carried out by members of the PSNI's economic crime bureau investigating the alleged scam after people were asked to contribute funds to facilitate the closure of a Stg£25 million Nigerian petroleum corporation contract.
Large returns were allegedly promised in exchange for assistance in the transferring of funds from Nigeria.
One Northern Ireland businessman lost Stg£2m last year, according to police in Belfast who are co-ordinating the inquiry.
He was one of a number of victims of the fraud, believed to be the largest of its type to date, a spokesman said. No arrests were made during today's operation.
The police spokesman added: "In the past fraudsters have deceived innocent investors with the promise of high returns with the sole intention of soliciting money in the form of the advance fees."
PA