Key ministers in the last government, and senior officials and advisers who worked with them, are expected to be interviewed by the Garda team investigating the leaking of official documents to newspapers. The leaders of the rainbow parties are expected to be among those interviewed during the investigation, aimed at discovering the source of three confidential memos printed in newspapers outlining views on the Fianna Fail/ Progressive Democrats presidential candidate, Prof Mary McAleese.
The Garda team, headed by Chief Supt Sean Camon and Det Supt Ted Murphy of the Garda's National Bureau of Criminal Investigation, is also investigating the source of documents obtained, but not published, by the Sunday Independent.
Gardai are expected to obtain a search warrant to retrieve copies of the documents from the Sunday Independent, after the newspaper refused to hand them over yesterday.
An office has been made available to the investigation team at the Department of Foreign Affairs, where the McAleese memos originated. Interviews have already started at the Department.
Fewer than 20 people may have had access to the "green box" memos compiled by Department officials gathering information on Northern Ireland, from which the McAleese memos were extracted.
The "green box" is a weekly compilation, generally of between 50 and 100 pages, for senior policy-makers handling Northern affairs. This would include ministers at the Departments of Foreign Affairs, the Taoiseach, the Tanaiste and Justice along with some ministers of state, secretaries of Departments and some of their senior officials.
One adviser to the last government, Mr Sean Donlon, has acknowledged he had access to "green box" documents, but he denied leaking them and said he did not retain copies.
Sources said the Garda team can interview "anyone who could assist" with the investigation. This would include those who might not themselves be suspected of passing on the documents to a newspaper, but could help the Garda determine who would have seen them.
The leak of the McAleese memos suggests that the leaker had access to green box memos for months or even years. Official sources said most copies of these documents are routinely destroyed in some Departments, but some may be retained. They are regarded as highly confidential.
The documents are not computerised, so the leaker appears to have had access to an unofficial collection of them, and to have trawled through thousands of pages of text to obtain the McAleese memos.
Leaking such documents is an offence under the Official Secrets Act, which allows for penalities including imprisonment for up to seven years.
On RTE's Questions and Answers programme on Monday, the Minister for Public Enterprise, Ms O'Rourke, said she would define the leaking as treason.
However, according to the Constitution (Article 39): "Treason shall consist only in levying war against the State, or assisting any State or person or inciting or conspiring with any person to levy war against the State, or attempting by force of arms or other violent means to overthrow the organs of government established by this Constitution, or taking part or being concerned in or inciting or conspiring with any person to make or to take part or be concerned in any such attempt."
The 1939 Treason Act did not widen the definition to include sending articles to newspapers. The 1990 Criminal Justice Act dealt with treason only to abolish the death penalty for the offence, changing the sentence to life imprisonment.