Drawing on personal experience, this practice note sets out lessons learned by two practitioners who were involved in bringing the case in the United Kingdom against Kumar Lama under universal jurisdiction. The authors start by setting out some guidance on strategic considerations in bringing a universal jurisdiction case, both in terms of fighting impunity in the country of origin and at the global level. They also include thoughts on using the outcome (which in this case was an acquittal). The practice note unpacks the potential legal and practical pitfalls involved. Throughout, the authors highlight the need to keep the complainants and witnesses’ interests at the centre of proceedings, and acknowledge how difficult that is across substantially different legal systems and cultures. At the heart of the work they identify a tension between human rights documentation principles and evidentiary rules applicable in any criminal prosecution. The practice note sets out how that applies to testimonial and documentary evidence, and stresses the value of and inherent risk in using contemporaneous evidence. In the absence of access to the country of origin by the prosecuting authorities (as was the case here), the practice note stresses the importance of building a team to do documentation with the understanding of its potential use as evidence in universal jurisdiction, ensuring a certain level of professionalism, and very importantly ensuring that confidentiality is guaranteed.