351.1 Mutual Assistance a. provisional measures indicate that the communication that is the subject of the request originated abroad; or b. the data was acquired by the executing authority based on an order for authorised realtime surveillance (Art. 269–281 CrimPC55). The data may not be used in evidence before the ruling on granting and the extent of mutual assistance is legally binding. 2 Notice of the ruling under paragraph 1 and any order or authorisation for surveillance must be given to the Federal Office immediately. 3 Art. 19 Choice of procedure If the defendant is abroad and if, according to the laws of the State to which the request is to be made, there is a choice between different procedures, preference shall be given to the procedure which appears to ensure the better social rehabilitation. Art. 20 Suspension of criminal proceedings or of the execution of a penalty At the request of the Federal Office, the competent authority may temporarily suspend criminal proceedings or the execution of a sentence against a defendant abroad for another offence if: 1 a. the sentence imposed in Switzerland is not of great importance in comparison to the one likely to be imposed abroad or b. execution of the sentence in Switzerland does not seem appropriate. On conclusion of the criminal proceedings abroad, the Swiss authority shall decide whether or not to resume the suspended proceedings or the execution of the penalty. 2 Art. 20a56 Transit In the interest of proceedings carried out in another State and permitted under this Act, the Federal Office may permit transit through Swiss territory and approve the measures required therefor on submission of a request by the State concerned or a third State without hearing the person concerned. There is no right of appeal against the decision and ancillary measures. They shall be notified only to the requesting State. 1 No approval shall be required if the detained person is to be transported by aircraft over Swiss territory without a stopover landing. In the event of an unscheduled stopover landing, the detained person may be kept in custody only if: 2 a. the requirements for his arrest under Article 44 are met; or b. the State arranging for the transport to be made has previously informed the Federal Office by indicating the reason for surrender and the offence which is the basis for it. Only the Federal Office may interrupt the transit to prosecute an offence or to execute a criminal judgment in Switzerland. 3 55 56 12 SR 312.0 Inserted by No I of the FA of 4 Oct. 1996, in force since 1 Feb. 1997 (AS 1997 114; BBl 1995 III 1).