Surveillance by police officers beyond state borders of a person suspected of being involved in an extraditable criminal offence.
In general cross-border observations have to be authorised on the basis of a request for mutual judicial assistance submitted in advance. If the surveillance is supposed to be executed for a longer period than 24 hours or on more than 2 days, the offence at stake has to be of considerable significance and surveillance is permissible only if other means of investigation would offer much less prospect of success or be much more difficult. In cases of particular urgency, in which prior authorisation cannot be requested, cross-border surveillance is permitted only for serious offences listed in Art. 40 para. 7, of the Convention implementing the Schengen Agreement, and has to be notified immediately, during the surveillance to the Federal Criminal Police Office in Wiesbaden. Furthermore, a request for assistance submitted in accordance with Art. 40 para. 1 and outlining the grounds for crossing the border without prior authorisation shall be submitted immediately.