Digital evidence in criminal investigations and the C.G. ruling: A shift in phone data access by police?

Abstract

The present paper examines a preliminary ruling on the principle of proportionality in criminal investigations involving digital data stored on mobile phones. The increasing reliance on technology in daily life has a significant impact on criminal proceedings. The data collected from these activities can provide insights into the private life of the user, which may be essential for law enforcement purposes. That said, police surveillance is a controversial debate. In October 2024, the CJEU issued the C.G. judgment (Case C 548/21), addressing the conditions under which investigating authorities can access such data under the Law Enforcement Directive. While the CJEU has previously interpreted access to retained data for criminal investigations by public authorities, this case introduces notable changes, particularly concerning the processing of location and traffic data for non-serious crimes. In this regard, the article compares the newest case with the Prokuratuur case (Case C-746/18) in order to illustrate the main differences. The C.G. case, read in conjunction with recent Union developments, such as the adoption of the e-Evidence Regulation, reflects a shift in the EU’s approach to these issues. Additionally, it highlights the fragmentation of domestic legal frameworks governing retained data, underscoring the challenges in achieving a harmonized approach.