The Public Accounts Committee (PAC) is to contact the Gardaí over "serious allegations" made against people linked to Rehab.
The PAC is to pass on a letter received from developer John Kelly, which the committee says outlines possible criminal offences.
The letter, sent through the developer's solicitors earlier this week, makes allegations against people currently, and formerly, linked to the Rehab Group.
Committee chairman John McGuinness said the PAC did not have the right to release the contents of Mr Kelly's letter.
"The allegations...fall outside the committee's remit and could potentially involve criminal wrongdoing," he said.
"The document is no longer a document of the committee's, and therefore, if published, does not have privilege (ie protection from defamation proceedings)."