This Note explores potential admissibility challenges that may arise when European courts use evidence of Syrian crimes collected by the newly-established International, Impartial and Independent Mechanism for Syria (the IIIM). The Note examines the evidentiary rules of four European countries—France, Germany, the Netherlands, and Sweden——where Syrian cases are currently being investigated or prosecuted. Specifically, it focuses on evidence that was improperly or illegally obtained, including evidence procured by private actors. This Note also looks at the European Convention on Human Rights (ECHR) Article 8 and relevant case law from the European Court of Human Rights concerning illegal searches and seizures. Finally, this Note highlights the importance of avoiding admissibility issues that may arise as a result of the IIIM's close cooperation with both private groups who gather the evidence on the ground and the European authorities that will ultimately be using such evidence in court.