Proving International Crimes elucidates how international criminal tribunals have tackled the immense and complex task of proving international crimes such as genocide, war crimes, and crimes against humanity. The challenges posed by the scale and scope of these crimes and the distance in time and space between their commission and their prosecution are well-known. Nevertheless, investigators, lawyers, scholars, and policy makers often look to the law and practice of international criminal tribunals to establish what standards need to be met in the collection, preservation, presentation, and analysis of evidence to prove international crimes. In offering a comprehensive account of the law and practice of evidence before international criminal courts and tribunals to date, as well as recommendations for future practice, this book aims to inform domestic, regional, and international accountability processes for crimes going forward. This book demonstrates that, owing to the flexibility built in to the legal and procedural frameworks of international criminal courts and tribunals, the law of international criminal evidence is often unpredictable and uncertain. To this end, McDermott argues for the development of a coherent epistemic framework driven by two guiding principles: rectitude of decision and the highest standards of fairness.