An opinion issued by a senior adviser to the European Union’s top court could have far-reaching consequences for criminal investigations going forward after he said that data-retention practices used by Irish police in a high-profile murder case contravened EU law.
In 2015, Graham Dwyer was convicted of the murder of childcare worker Elaine O'Hara three years previously, with the data gathered by authorities from mobile phones being key to the guilty verdict.
The case came to the European Court of Justice following an appeal by Dwyer who argued that Ireland’s data retention law was contrary to the bloc’s legislation on the matter.
Manuel Campos Sánchez-Bordona - one of the ECJ’s 11 Advocate Generals who advise the top courts’ judges - argued in a court statement on Thursday that "general and indiscriminate retention of traffic and location data" is only permitted “in the event of a serious threat to national security”, for example, terrorist cases.
He added that murder cases do not apply.
The opinion, which is not an official ruling, is usually followed by ECJ judges and precedes any decision made by the court to assist it in a final judgment.
According to Gianclaudio Malgieri, an Associate Professor of Law and Technology at the EDHEC Business School in Lille, the court’s justices will probably agree with the Advocate General’s opinion.
“This opinion is likely to be confirmed by the court because it clearly builds on previous case law of the court, so it's not built on previous Advocate General opinions, but it's built on two recent cases from the court,” Malgieri told Euronews.
If the opinion is upheld it could shape how police across the continent gather evidence, potentially limiting their ability to harvest and utilise mobile phone traffic and location data in criminal investigations.
The Irish authorities argue that Dwyer’s conviction would not have been possible without being able to use the data found on mobile phones linked to the imprisoned killer.
His legal team, however, say that police were able to use his telephones as “personal tracking devices”, going against his civil liberties.
Campos Sánchez-Bordona also pointed out that the decision to access mobile phone data in Ireland is made at “the discretion of a police officer of a certain rank”, adding that this goes against previous EU case law, which states that access to data like this must be “subject to prior review by a court or an independent authority”.
Malgieri says the Advocate General did not believe that the decision to access Dwyer’s data was made by someone deemed to be independent and not linked to the investigation.
"An important implication for ongoing investigations and ongoing activities is that there should be an ex-ante authorisation by an independent authority, which in this case was not considered to be independent because it was just a public prosecutor," Malgieri said.
"And so, the advocate general believed that the public prosecutor is not independent from the government," he added.
A decision is expected around March next year.