Unlawfully Obtained Evidence, Cross-Border Law Enforcement Operations and Borderless Networks

In certain jurisdictions, national evidence law rules may prohibit the use of illegally or unlawfully gathered evidence in criminal proceedings, or at least give the court the possibility to exclude illegally gathered evidence under certain circumstances. However, when it comes to cross-border investigative measures in the global and borderless network environment, it may not always be clear what “unlawfully obtained” or “illegally obtained” actually means. This paper discusses the different possible meanings of illegality/unlawfulness in the context of such investigative operations. The discussion is based on the examples of Finnish law and case law pertaining to evidence derived from the supposedly secure ANOM messaging application, widely used by criminals, in the international law enforcement operation known as Operation Trojan Shield/Greenlight.