Federal Supreme Court, 12.02.2026, 7B_612/2025
Facts
As part of an investigation into major drug trafficking, the Geneva Public Prosecutor's Office ordered covert surveillance measures (geolocation and audio recording) between May and August 2024 on four vehicles used by the defendant and an accomplice. The devices were installed in Switzerland.
As the investigation revealed that the vehicles frequently traveled to France, the Public Prosecutor's Office submitted two requests for mutual legal assistance to the French authorities (on June 13 and September 16, 2024) to obtain authorization to use the data collected on French territory. The French authorities granted these authorizations.
Following his arrest in September 2024, the defendant requested the removal and destruction of the data collected in France prior to obtaining the mutual assistance authorizations, arguing that it was obtained unlawfully. His request was rejected by the Public Prosecutor's Office and subsequently by the Criminal Appeals Chamber of the Geneva Court of Justice. The defendant appealed to the Federal Supreme Court.
Legal Analysis
The Federal Supreme Court reaffirms the principle of territoriality, according to which a state may not carry out criminal prosecution acts on the territory of another state without its consent. In the absence of a specific international treaty governing the use of cross-border technical surveillance methods (as the 3rd Additional Protocol to the European Convention on Mutual Assistance in Criminal Matters is not in force), the consent of the foreign state must be obtained through mutual legal assistance.
In principle, this consent must be obtained in advance. However, the Federal Supreme Court acknowledges that a retroactive request for mutual assistance is conceivable in certain situations, particularly when the crossing of the border is unforeseeable.
However, to address the lack of a legal basis and the issue of reciprocity (Art. 30 of the Federal Act on International Mutual Assistance in Criminal Matters), as Switzerland cannot grant a foreign state what its own law does not permit, the Federal Supreme Court sets two cumulative conditions for the validity of such a retroactive request:
- The request for mutual assistance must explicitly inform the requested state that Switzerland would not be able to grant reciprocity in a reverse situation. This information is crucial for the requested state to provide its consent with full knowledge of the facts, in accordance with the principle of good faith in international law.
- The request for mutual assistance must be filed "without delay" as soon as the Swiss authorities become aware that the monitored vehicle has crossed the border.
Application to the present case
The Federal Supreme Court examines whether the conditions for a retroactive mutual assistance request are met. It focuses on the first condition: information regarding the lack of reciprocity.
The Federal Supreme Court notes that Swiss law (notably Articles 67a and 80d bis of the Federal Act on International Mutual Assistance in Criminal Matters) would not allow Swiss authorities to authorize foreign authorities to collect data directly and in real-time on Swiss territory prior to any request for mutual assistance. Consequently, Switzerland cannot guarantee reciprocity in a case such as this one.
Requests for mutual legal assistance sent to France should therefore have included an explicit warning on this matter. However, the cantonal court's judgment contains no factual findings to verify whether this mention was included in the Public Prosecutor's requests. As this factual element is essential for assessing the lawfulness of the evidence, the Federal Supreme Court cannot rule on the merits.
Outcome
The Federal Supreme Court allows the appeal. It sets aside the judgment of the Criminal Appeals Chamber and remits the case to it.
The cantonal authority must complete the statement of facts by verifying whether the mutual legal assistance requests sent to France contained the required warning regarding the lack of reciprocity. If this is not the case, the data collected in France must be declared inadmissible and destroyed, along with any evidence derived from it.
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