Police investigations in Internet open sources: Procedural-law issues

Analysing large amounts of data goes to the heart of the challenges confronting intelligence and law enforcement professionals today. Increasingly, this involves Internet data that are ‘open source’ or ‘publicly available’. Projects such as the European FP7 VIRTUOSO are developing platforms for open-source intelligence by law enforcement and public security, which open up opportunities for large-scale, automated data gathering and analysis. However, the mere fact that data are publicly available does not imply an absence of restrictions to researching them. This paper investigates one area of legal constraints, namely criminal-procedure law in relation to open-source data gathering by the police. What is the legal basis for this activity? And under what conditions can domestic and foreign open sources be investigated?