Facts

Parties involved: A. (the appellant), the Public Prosecutor's Office of the Eastern Vaud district, the Coercive Measures Court (Tmc), the Vaud cantonal police.

Court: Federal Supreme Court, First Public Law Chamber.

Date of the decision: November 15, 2019.

Main facts:

  • The Vaud cantonal police discovered a network of drug traffickers operating on the Vaud Riviera.
  • Various technical measures, including the placement of GPS trackers and microphones, were authorized by the Tmc and the Public Prosecutor's Office.
  • Recordings made abroad (Spain, France, Germany, Kosovo, Albania) without authorization from foreign authorities are contested by A.
  • The Tmc authorized the use of data discovered fortuitously during the surveillances.
  • [A.] requested the removal of recordings made abroad without authorization and the inadmissibility of this evidence.
  • The Public Prosecutor's Office refused, considering the recordings admissible.
  • The Criminal Appeals Chamber of the Vaud Cantonal Court dismissed the appeals of [A.] and C.
  • [A.] filed a criminal appeal against this decision.

Considerations

2.1 Technical surveillance measures, such as the placement of microphones and GPS trackers, are coercive measures that intrusively infringe on the private sphere. They are governed by Articles 280 to 281 CrimPC, which provide strict conditions for their implementation. Article 272 CrimPC requires authorization from the Tmc for the surveillance of postal and telecommunication correspondence. The results of unauthorized surveillance are inadmissible and must be immediately destroyed (Art. 277 para. 1 and 2 CrimPC).

2.2 Under the principle of territoriality, a State cannot exercise its sovereign prerogatives, including coercive measures, on the territory of another State without the latter's consent. Acts of public authority carried out without this consent are inadmissible and constitute a violation of public international law. Technical surveillance measures, such as wiretapping, are subject to this principle. Cross-border observation and secret investigation also require prior authorization or an international treaty.

2.3 In this case, the microphones were installed in Switzerland, and the authorizations were obtained in accordance with the CrimPC. However, the Public Prosecutor's…