Police have opened an investigation into allegations of a political pay-off from the biggest property deal ever sealed in Northern Ireland.
It follows mounting calls for a criminal probe into claims surrounding the £1.3bn sale of Nama's Northern Ireland loan book.
The 850-property portfolio was bought by a US investment firm in April 2014.
Last week independent TD Mick Wallace claimed that £7m in an off-shore bank account linked to the deal had been earmarked for a Northern Ireland politician.
Yesterday the PSNI confirmed the allegations were now the subject of a criminal inquiry.
Assistant Chief Constable Will Kerr said: "We believe that there is sufficient concern in relation to potential criminal activity, surrounding this property deal, to instigate an investigation.
"PSNI are now engaging with a number of other national and international law enforcement partners to consider how best to take forward this investigation."
It is understood the other law enforcement organisations include the National Crime Agency, the FBI-style body that recently became fully operational in Northern Ireland.
Detectives will examine in detail the claims made by Mr Wallace surrounding the Nama sale.
Mr Wallace named Belfast law firm Tughans as having acted for Cerberus Capital Management, the New York-based company behind the £1.3bn buy-up. The purchase price was a £3bn-plus writedown on the portfolio's £4.5bn face value.
Mr Wallace said a routine audit showed that £7m ended up in an Isle of Man bank account, adding: "It was reportedly earmarked for a Northern Ireland politician."
Tughans have strenuously denied any wrongdoing. Last night a spokesman said Tughans would co-operate fully with any PSNI inquiry and intended to contact police at the earliest opportunity
The company confirmed that its former managing director Ian Coulter diverted professional fees to an account without its knowledge. Mr Wallace's allegations are the subject of political inquiries in both Dublin and Belfast. The Dail's Public Accounts Committee is due to quiz Nama officials today, while Stormont's finance committee is also investigating the claims.
News of the police investigation has been welcomed.
A DUP spokesman said: "This is a welcome announcement and the appropriate step to deal with the serious allegations which have been made.
"Indeed, the First Minister called for such action by the authorities last week noting that accusations of criminal behaviour tarnish politics and should be fully investigated. We trust everyone concerned will co-operate fully with the PSNI team."
April 5, 2014: US firm Cerberus Capital Management buys Nama's entire Northern Ireland portfolio in a £1.3 billion deal.
July 2, 2015: Independent TD Mick Wallace uses parliamentary privilege to allege £7m contained in an Isle of Man bank account was earmarked for a politician in Northern Ireland.
July 6, 2015: PSNI confirms that, fours days after Mr Wallace's claims, it is still not investigating the matter. TUV leader Jim Allister says he is "amazed".
July 7, 2015: Law Society calls for evidence about the sale of Nama's Northern Ireland portfolio to be given to police.
July 8, 2015: PSNI confirms it has launched a criminal inquiry into the sale of Nama's Northern Ireland property portfolio.