Access to personal data held by electronic communications service providers in criminal investigations according to the Court of Justice of the EU

The EU Court of Justice recognises that accessing, holding and transferring electronic personal data, pretrial proceedings which are becoming more and more commonly used in criminal proceedings, constitutes interference in the fundamental rights to private and family life and to personal data protection, and therefore if a public authority attempts to obtain such data, it requires judicial authorisation which must in all cases respect the principle of proportionality and establishes, as a criterion of the evaluation of proportionality, the seriousness of the crimes. It seems, then, that access to electronic personal data in criminal investigation must be strictly limited to the purposes of prevention and the detection of serious crimes, or the trial of such crimes. This leads to the doubt which we attempt to resolve in this work: Can only the examining judge authorise obtaining electronic personal data held by communications service providers when serious crimes are being investigated? Or, in a criminal investigation, should proceedings for obtaining evidence and access to electronic personal data be authorised when the crime is not serious? The CJEU recently gave a response which requires analysis, as it serves to set important criteria that the examining judge must use in the judgement of proportionality which gives the foundation for the authorisation of these kinds of criminal pretrial proceedings.