In her opening address at the 24th Annual National Prosecutors’ Conference (25 November), the Director of Public Prosecutions (DPP) Catherine Pierse highlighted the development of smartphones as one of the biggest game-changers in the criminal-justice landscape in recent years.

Most criminal cases now involve evidence from smartphones or other digital devices. The DPP told the 300 delegates at The Convention Centre Dublin that the proliferation of digital data had “utterly transformed the volume and nature of material that is gathered at the investigative stage”.

This material must be assessed when deciding whether to prosecute, reviewed at the disclosure stage, and then ultimately presented at trials, she said.

At a practical level, Pierse stated that it was important to create a common understanding of who was responsible for doing what as part of this process – in particular with regard to investigators and the prosecution service.

With this in mind, the Office of the DPP has been working with An Garda Síochána over the past year to embed improved practices on the communication of mobile-phone data. It has also been collaborating with the gardaí to identify the most appropriate technical solutions to support the interrogation of this data.

Dwyer case

One of the issues raised by the digital era is the need to balance privacy and data-protection rights with the public interest in the prosecution of criminal offences and fair-trial rights.

When dealing with millions of records, there are real, practical difficulties in being specific about what is potentially relevant – this becomes acute where a crime may not even have been committed or come to light yet, according to Pierse.

She cited the Irish case of Dwyer v Commissioner of An Garda Síochána, where Graham Dwyer appealed his conviction in 2015 for the murder of Elaine O’Hara on the grounds that the Communications (Retention of Data) Act 2011 was invalid.

He had been identified as a suspect a year after her disappearance, using location data from mobile phones recovered from a reservoir.

In this case, the European Court of Justice found that indiscriminate retention of data was in breach of the Charter of Fundamental Rights, but that it might be permissible in certain circumstances to request that data be retained in respect of particular suspects or locations.

The Communications (Retention of Data) (Amendment) Act 2022 was a response to European Court of Justice rulings on data retention – including in the Dwyer v Commissioner of An Garda Síochána case.

Mobile-phone evidence

The DPP noted that the Irish courts had also been considering how specific investigators needed to be when seeking authorisation to search and seize potential evidence. Most recently, in DPP v Patrick Quirke, the Supreme Court identified a distinction between physical places and the digital space in this regard.

“Over the past number of years, lengthy arguments relating to the admissibility of mobile-phone evidence and other digital data have been a feature of many trials,” said Pierse.

“From a human-rights perspective, it is crucial that there is certainty for investigators that the powers they exercise accord with national and European law, and that they can know the precise parameters of those powers.”

She acknowledged that work was underway to address some of the broader issues with the drafting of the Garda Síochána (Powers) Bill. At an EU level, the e-Evidence Regulation and directive, effective from February 2026, will provide harmonised rules on the gathering of electronic evidence.

Disclosure of counselling records

Moving to the prosecution service’s disclosure obligations, Pierse explained at the National Prosecutors' Conference that it was sometimes necessary to assess intensely personal information contained in counselling, medical and social-work records, in addition to those on mobile phones.

“We need to exercise real discipline in assessing whether such records are actually relevant because, unless they are, then it cannot be justifiable to disclose them, given their sensitivity,” she said.

Since 2018, section 19A of the Criminal Evidence Act 1992 puts in place a process for judicial oversight in respect of the disclosure of counselling records.

Published in 2020, the O’Malley Review of Protections for Vulnerable Witnesses recommended that a similar provision be put in place for medical records. In Pierse’s view, there are other categories of sensitive data where a similar judicial-oversight process could be usefully employed.

“I think it’s time to consider whether there is a more effective means to identify relevant documents for disclosure. For example, is there a way to introduce an enforceable requirement on all parties to engage at an early stage about relevancy?” she said.

“Given the evolution of data and the impact on prosecutions, it is evident that current procedures have been overtaken by the digital age. It is incumbent on us to move the debate forward on this matter, and this is something my office will be seeking to do in 2024.”