The National Crime Agency - the British equivalent of the FBI - is to lead the investigation into the purchase of the property portfolio of NAMA, and claims about money contained in an Isle of Man bank account.
It is understood the PSNI asked the NCA to take the lead because of the complexity and scale of the investigation.
This will be the first major investigation of the NCA since it began operating in Northern Ireland in May.
Investigators from the agency are expected to meet the PSNI shortly.
The chairman of NAMA has said any money diverted to the Isle of Man after the sale of NAMA loans in Northern Ireland did not come from the agency, nor the money that was due to be paid to a former NAMA advisor Frank Cushnahan.
Mr Cushnahan was set to receive £5 million for advising a rival bidder, Pimco, which had to pull out when NAMA was told of his role.
Public Accounts Committee member Shane Ross says the whole sale should have have been stopped when Pimco was told to withdraw:
Frank Daly has told the PAC that the agency was not aware of any funds being set aside until recent days.
"If a payment did find its way to an account in the Isle of Man - as has been alleged - then wherever such a payment came from, it most certainly did not come from NAMA or from proceeds that were due to NAMA under this sale," he said.
"In fact, NAMA had no knowledge of this alleged payment to Mr Coulter by Brown Rudnick until recent days when it was put into the public domain" he added.
Earlier, the agency released a statement - claiming NAMA sold its Northern Irish loan book for its full value "and not a cent less".
Around 850 assets were sold in one lot for over €1.5bn last year.
But in the Dáil last week, Independent Deputy Mick Wallace claimed they were worth in the region of €4.5bn - a claim NAMA strenuously denies.
"The assets may - years earlier - have been worth more but the fall in their value was a result of the property crash and they were not worth anything more that the price NAMA achieved when sold by NAMA," it added.
