Gardai today arrested one of their colleagues over the leaking of a letter that led to the resignation of former junior minister Trevor Sargent.
The female officer, in her early thirties, was taken to Lucan Garda Station for questioning about how correspondence from the former Green Party leader was passed to a newspaper.
The revelations that Mr Sargent wrote to a garda in 2008 asking for a public order prosecution against a constituent to be dropped forced him to stand down last month as minister of state for food and horticulture.
A second letter from the Dublin North TD was written to a garda superintendent as late as February 15 this year in connection with the case.
The garda officer arrested at her home at around 10.20am was suspended from the force pending the outcome of an investigation into the leaking of the correspondence to the Evening Herald newspaper.
She was previously based at Balbriggan Garda Station but recently moved to Garda Command and Control at Harcourt Square in central Dublin.
"She is currently detained at Lucan Garda Station under section four of Criminal Justice Act," said a garda spokeswoman.
Under the Garda Siochana Act, an officer can face a 50,000 euro fine or up to five years in jail for disclosing confidential information.
Garda Commissioner Fachtna Murphy ordered an internal probe into how the information was leaked after a political storm about who was responsible.
Justice minister Dermot Ahern denied it was a tit-for-tat attack by Fianna Fail on their Green Party coalition partners after the resignation of defence minister Willie O'Dea.
The revelations about Mr Sargent emerged just days after Mr O'Dea was forced to resign under pressure from the Greens because he wrongly claimed a Sinn Fein councillor had links to a brothel, but denied the slur on a sworn High Court affidavit.