This article focuses on the practical and legal-normative challenges and opportunities for cross-border criminal crypto investigations. Cryptocurrencies are (mis)used in various criminal activities. Law enforcement agencies worldwide attempt to detect these crimes. A case study of the Netherlands shows that data from crypto exchanges is often crucial for locating a suspect. However, in many cases this information is located abroad or in multiple jurisdictions, or it is unknown where it is, or the involved public and private actors do not agree on what governs enforcement jurisdiction. In such cases, traditional ways of international cooperation – i.e. the MLA system – seem to be inadequate. As a result, alternative and informal evidence-gathering practices emerge, including unilateral actions.