So what actually happened and when?
2008: Sgt Maurice McCabe writes to garda headquarters alleging neglect of duty and various malpractices by gardai. He also claims he is being victimised. Chief superintendent investigates allegations.
Later in 2008: Sgt McCabe makes anonymous complaint to the then Garda Commissioner through the then confidential recipient, Brian McCarthy. An Assistant Commissioner is appointed to investigate.
2009: Sgt McCabe makes two further harassment and victimisation complaints to the Garda Commissioner. Allegations investigated by garda headquarters.
Sgt McCabe also writes to the then Justice Minister, Dermot Ahern, alerting him to his allegations of malpractice.
2009: Sgt McCabe initiates a defamation action against the State and Garda Commissioner.
2009: Assistant Commissioner forwards 10 volumes of evidence to DPP which directs that no prosecutions were warranted.
June 2010: GSOC is informed of Assistant Commissioner's investigation and the DPP's decision not to prosecute. GSOC investigates a number of the complaints but does not recommend further action.
2011: Sgt McCabe takes bullying and harassment case against An Garda Siochana.
Jan 23, 2012: Justice Minister Alan Shatter receives report from garda confidential recipient, Oliver Connolly, detailing 12 allegations from Sgt McCabe about a superintendent who was promoted by the Garda Commissioner.
Jan 24, 2012: Mr Shatter instructs his secretary general to write to the Garda Commissioner seeking an "urgent" report.
Jan 30, 2012: Commissioner responds saying 11 of the 12 allegations had been "dealt with". The final allegation related to the rape of a minor, and Mr Shatter was told this was "fully investigated in accordance with the law in place at the time".
Feb 7, 2012: Mr Shatter writes to the confidential recipient and informs him of the response from the Garda Commissioner.
Sept 4, 2012: A solicitor for Sgt McCabe sends Mr Shatter further allegations of garda wrongdoing and requests a special inquiry. Some allegations relate to penalty points.
Oct 18, 2012: Mr Shatter responds asking can he forward the confidential information to the Garda Commissioner and also asks to waive Sgt McCabe's anonymity. He later sends a reminder.
Dec 2012: Mr Shatter writes to the Garda Commissioner detailing some allegations which overlapped with previous concerns raised by Sgt McCabe.
Jan 3, 2013: Mr Shatter sends a reminder to Sgt McCabe's solicitor. Solicitor responds saying relevant information has been sent to the Taoiseach.
Feb 2013: Commissioner gives "detailed response" to Mr Shatter's December correspondence.
Mar 11, 2013: Mr Shatter replies to Sgt McCabe's solicitor saying information with Taoiseach differs from the complaints he received.
May 1, 2013: Sgt McCabe's solicitor seeks copy of O'Mahony report.
May 22, 2013: Mr Shatter again seeks to waive the garda's right to confidentiality.
Feb 26, 2014: Mr Shatter says he will forward the complaints from Sgt McCabe's solicitor to barrister Sean Guerin who is carrying out a review of the affair.