Introduction

The rise of new generation technologies allows for the gathering and the swift analysis of vast amounts of biometric data. Against this background, the research aims at proposing an adequate reform of the criminal law of evidence, striking a balance between competing claims: the protection of fundamental rights and the right to a fair trial on the one side, the investigation of criminal activities on the other. The legal system clearly struggles in keeping up with the latest technological developments but, in the domain of biometric data, the situation is dire: the lack of an adequate legal framework can produce unexpected, concerning consequences. In this domain, the technology is evolving fast and it can be particularly pervasive. For example, wearables and smart assistants can record biometric data; drones are equipped more and more frequently with facial recognition software to surveil territory, to identify suspects, to search for missing people. The tool has become quite common in practice in spite of the alarming lack of legal regulation and of the extreme fragility of the data that can be collected, stored and produced as evidence. In the overall picture of data that are available in the globalized world, biometric information is the most delicate sub-set: it can reveal the most intimate characteristics of an individual and they would deserve an enhanced protection. The tools that can gather them, moreover, are particularly intrusive of the nature of the information collected and the manner in which they can gather data. Drones can follow a predetermined target and identify it anywhere; devices that are materially attached to the human body can record a person’s reactions; AIs can record a person’s voice to execute commands: they are the most eminent examples of the variety of tools that technology can offer to this regard. Storage and cross-border exchange of said data show peculiar issues. Data bases are getting richer, more complex and interoperable at a continental level. Hence, issues concerning chain of custody, secure methods of storage and circulation have become urgent; The same goes for the legal questions that this architecture raises, such as the limits to the evidentiary use of data that have already been introduced in the system. Since gathered data are piled up in a huge trove of information that law enforcement agencies can access, the need has arisen for a comprehensive research on the normative standards that should regulate the phenomenon.