In its decision ruling 6B_525/2024 of 15 January 2025 (scheduled for publication in the Official Collection of Decisions), the Federal Supreme Court has issued a leading decision on the scope of the nemo tenetur principle: Law enforcement authorities are not entitled to request the disclosure of PIN codes or other access credentials to mobile devices during a house search without first explicitly informing the accused of their right to remain silent and their right to refuse cooperation. Since revealing such access data may constitute active participation in self-incrimination, it falls under the right to refuse cooperation pursuant to Article 158 para 1(b) of the Swiss Code of Criminal Procedure (CrimPC). As a result, an accused person cannot be compelled to disclose a PIN code or password.
Facts of the case
During a house search, police officers requested an accused person to disclose the PIN code of their mobile phone without first informing them of their procedural rights. The authorities justified this approach by arguing that it was necessary to facilitate the house search and classified the request as a purely administrative measure.
Federal Supreme Court's Considerations
The Federal Supreme Court rejected this practice, holding that requesting a PIN code without prior notification of rights constitutes a violation of the nemo tenetur principle and Article 158 CrimPC. The key considerations are as follows:
- If a person is considered a suspect, they must be informed of their right to remain silent and refuse cooperation. Informal questioning by the authorities in order to circumvent this obligation is impermissible. The instrument of informal questioning must not be used to undermine the statutory procedural guarantees of Articles 158 and 159 CrimPC.
- According to prevailing legal doctrine, the concept of interrogation must be understood in a substantive rather than merely formal sense. The decisive factor is whether a statement was elicited by a law enforcement authority. If so, the situation qualifies as an interrogation, requiring a prior notification of rights.
- Law enforcement authorities cannot justify requesting a PIN code merely as a means of facilitating a house search, as such a request constitutes an interrogation in the material sense.
- Any PIN code disclosure obtained without prior notification, along with all information derived from it, is absolutely inadmissible as evidence (Article 141 para 1 CrimPC). Furthermore, any derivative evidence obtained as a result of the unlawfully acquired PIN code is also inadmissible under Article 141 para 4 CrimPC (the "fruit of the poisonous tree" doctrine), unless it could have been lawfully obtained through independent means. In the present case, this was not the case, leading to the exclusion of all related evidence.
- The nemo tenetur principle protects the right against self-incrimination. A valid waiver of this right requires that the individual concerned has been informed of it in advance and demonstrably understood its implications. This requirement is even more critical when the information provided is incorporated into the criminal case file, whether in the form of transcripts, notes, or reports, regardless of whether these are recorded in a police vehicle, en route to an inspection, or during a house search.
Practical Implications
Persons accused in criminal proceedings are not obliged to disclose PIN codes or passwords. Any such request should be refused by invoking the right to remain silent. House search protocols must be carefully reviewed to determine whether access credentials were obtained without prior notification of rights. If so, the inadmissibility of the evidence must be asserted.
With this decision, the Federal Supreme Court sends a clear signal in favor of safeguarding procedural rights in criminal proceedings. Law enforcement authorities are required to strictly observe the notification obligations set out in Article 158 CrimPC. This ruling not only strengthens the rights of accused persons but also clarifies the limits of permissible investigative measures in the context of house searches and digital evidence.