The government has published the terms of reference for an investigation into the Garda whistleblower affair.

Senior counsel Sean Guerin will have until Easter to recommend whether a full commission of inquiry should be ordered.

But he won't be able to investigate the controversy about whether the whistleblower Maurice McCabe co-operated with the penalty points investigation.

Mr Guerin has been explicitly asked to interview Sergeant McCabe, as well as anyone else who might be relevant in his allegations.

Garda confidencial recipient

That could include the Garda confidential recipient, Oliver Connolly, who previously brought the claims to the attention of the Department of Justice - and who was sacked last week.

He can also examine all documents and data held by the Department and the Gardaí, and review the responses from the Gardaí - and potentially the Director of Public Prosecution.

Mr Guerin doesn't have any remit to investigate the penalty points issue - that's instead being left to the Garda Ombudsman.