GSOC: the timeline
December 2005: Three-member Garda Siochana Ombudsman Commission set up to oversee and investigate complaints against members of the gardai. Replaces the Garda Siochana Complaints Board.
February 10, 2006: Carmel Foley, former director of consumer affairs, appointed to Commission.
December 12, 2011: Simon O'Brien, former London police officer, and former journalist Kieran FitzGerald are appointed to the Commission.
September 23-27, 2013: A security sweep to check for any eavesdropping or spying devices was carried out at the offices of the Commission in Dublin by specialist security firm Verrimus from the UK. Three technical and electronic "anomalies" raised concerns about integrity of the telecommunications system.
December 17, 2013: Overall investigation into possible interception of communications completed. Decision taken to improve security of communications systems. Justice Minister and garda authorities not informed.
February 9, 2014: A Sunday newspaper reports that there were attempts to spy or bug the offices of the commission and that it may have been accomplished with a hi-tech level of expertise normally associated with state agencies.
February 10: Justice Minister Alan Shatter summons Mr O'Brien to his office to explain the situation and also why he and the gardai weren't told. Mr O'Brien issues a statement, stating the existence of the anomalies "could not be conclusively explained". He stated there was "no evidence of garda misconduct" and expressed regret for not reporting the matter at the time.
Garda Commissioner Martin Callinan states he is gravely concerned that the Ombudsman's statement appeared to contain a clear indication that An Garda Siochana was in some way suspected.
February 11: Association of Garda Sergeants and Inspectors calls on Mr O'Brien to "consider his position" as chairman of the commission, while the Garda Representative Association calls for a public inquiry into the situation. Mr Shatter tells the Dail that the GSOC told him there was no evidence that its offices had been bugged with technical or electronic surveillance.
Mr Shatter said it was unfortunate that An Garda Siochana appeared to be the subject of "completely baseless innuendo" that they may have been in some way connected to the controversy.
February 12: The Ombudsman is quizzed by TDs and senators at the Oireachtas Joint Committee on Public Service Oversight, which has declared its "deep unease" at the bugging claims.
February 19: Then Justice Minister Alan Shatter sets up an independent inquiry into the garda watchdog bugging controversy, chaired by recently retired High Court judge John Cooke. On the same day he tells the Dail that a "peer review" of the technical information from an Irish-based IT security consultancy firm, RITS, found "no evidence at all, not merely no definitive evidence", of any technical or electronic surveillance of GSOC.
March 25: Garda Commissioner Martin Callinan resigns. He states that recent developments were "proving a distraction" to the work carried out by the gardai.
May 7: Mr Shatter resigns as Justice Minister, claiming it is his "duty" to resign after the Guerin report found there was an inadequate response to garda whistleblower Sergeant Maurice McCabe's reporting of confidential information.
May 9: Government publishes report by Sean Guerin SC into allegations of garda misconduct. Mr Guerin recommends a comprehensive Commission of Investigation be established to investigate the issues that "remain unresolved" arising from complaints made by whistleblower Mr McCabe.
Jun 10: Cooke report into alleged bugging of Garda Ombudsman's office finds GSOC overstepped the mark in setting up a special investigation into their suspicions of surveillance. However, it has "no evidence" to back up the claim surveillance was carried out.