Act gave GSOC far reaching powers
Under laws enacted last year, the Garda Síochána Ombudsman Commission (GSOC) was granted garda-style powers in relation to access to phone and email records.
For years gardaí of the rank of chief superintendent and above have been able to request such records from phone companies, internet service providers and email services.
The new laws bestowed the same privileges on GSOC investigators.
Critics say it means they can get access to such records without having to apply to a judge or inform the individuals involved that their records are being accessed. Indeed, the two journalists at the centre of the current GSOC investigation only found out from external parties that the commission had been scrutinising their records.
The legislation was brought in by Justice Minister Frances Fitzgerald against the backdrop of several controversies in the garda force in recent years.
The Garda Síochána (Amendment) Act 2015 was a far-reaching piece of legislation which effectively added GSOC into a number of acts governing garda investigative practices.
The legislation amended a range of acts dealing with issues such as surveillance and the interception of postal packets and telecommunications messages.
It was seen as a way of strengthening the powers of GSOC.
However, it is unlikely legislators envisaged that the first high-profile use of the act by GSOC would be to gain access to the phone records of journalists, possibly across a two-year period.
Under Irish law, telephone companies must retain call and text records for 24 months.
Cell site information, which gives the rough location of a mobile phone when a specific call is made, must also be kept for two years. Email records must be kept for one year.
Investigators can seek information not just on emails, but also when a person logged on or logged off from a specific internet service.
Phone records have played a key part in a number of garda criminal investigations in the past, including the murder of Dublin woman Rachel O'Reilly by her husband Joe.
Cell site analysis helped place the advertising executive at the family home on the day of the murder, when he had claimed to be elsewhere.