Zurich High Court: SkyECC data absolutely inadmissible for violation of Swiss sovereignty

By decision of 15 August 2025 the Second Criminal Chamber of the High Court of the Canton of Zurich held that the SkyECC data in the file are absolutely inadmissible and ordered their removal. The man-in-the-middle device authorised in France sent a hidden push message to each SkyECC handset to make it release its decryption keys. For the accused, whose phone was in Switzerland, this intrusion took effect on Swiss territory without any request for mutual legal assistance, which violated Swiss sovereignty and the territoriality principle. Under the case law of the Federal Supreme Court (BGE 146 IV 36), such evidence cannot be used under any circumstances; the balancing exception for serious offences in Art. 141(2) CrimPC does not apply, and the records must be removed under Art. 141(5) CrimPC. The court added that mere use of an encrypted phone cannot found the urgent suspicion required for surveillance.