The European union's top court stated on Tuesday that Irish authorities breached the law by using mobile phone data during a 2015 murder investigation in a ruling that could have repercussions around the bloc.
In its ruling, the Court of Justice of the European Union confirmed "that EU law precludes the general and indiscriminate retention of traffic and location data relating to electronic communications for the purposes of combating serious crime."
Convicted murdered Graham Dwyer, currently serving a life sentence for the 2015 killing of childcare worker Elaine O’Hara, had argued in its appeal process that the retention of and access to that data infringed the rights proferred to him by EU law.
Tuesday's ruling is therefore a win for Dwyer but a blow to the Irish state and police who say they would never have known Dwyer was complicit without the access and retention of his data.
Messages between Dwyer and his victim as well as geolocation data helped Irish prosecutors piece together the last living day of the 37-year-old O'Hara, and helped the jury decide to put him behind bars for life.
But for Europe’s highest court it goes a step too far into the private life of individuals.
Professor Tobias Lock, Jean Monnet Chair in EU law, concurred with the ruling.
"If we all know in Europe that our data will be retained for a year, all the communication data, that might actually have a chilling effect on us communicating with anybody," he told Euronews.
"We might not make use of our freedom of speech, freedom of expression that we have, as we are afraid of being found out, and that chilling effect is an important motivating factor for the court of justice as well," he added.
What this means is that there may indeed be another trial for Graham Dwyer but this latest decision may not be his get-out-of-jail card as prosecutors had other evidence against him. But the ruling could, however, have implications for other cases in Ireland and across the EU.