Cross border surveillance (or observation) on an alleged perpetrator (or a person linked to the perpetrator) is a special intelligence operation carried out from the territory of a foreign country into the territory of Bulgaria or the other way round and in the course of investigation of an extraditable offence/crime which cumulatively is a serious intentional crime - punishable with over 5 years of imprisonment under the Bulgarian Criminal Code, and explicitly listed in Article 172 of the Criminal Procedure Code of the Republic of Bulgaria. The measure is a type of special intelligence means applicable for the investigation of crimes, which are explicitly specified in the Convention implementing the Schengen Agreement of 14 June 1985 or in an international treaty, to which the Republic of Bulgaria is a party, by virtue of which their use is allowed (e.g. the Second Additional Protocol to European Convention on Mutual Assistance in Criminal Matters of 1959).
During the surveillance different aspects of the activity and behavior of persons during their movement and residence are revealed and documented.
The measure is executed on request for legal assistance for continuation the surveillance, sent in advance to the Bulgarian Supreme Prosecutor's Office of Cassation. The measure is not in the scope of the Bulgarian EIO Act. The Supreme Prosecutor's Office of Cassation rules on the acceptance of the request and, if it grants it, submits a written reasoned request for permission to the Chairman or to an authorized deputy - chairman of the Sofia City Court. The request must contain: 1. information about the crime and the investigation; 2. data on the persons against whom the cross-border surveillance will be carried out; 3. which employees will carry out cross-border surveillance (the common principle is that officers from the requesting state continue their observation in the territory of the requested state but on explicit request the observation can be entrusted to officers of the state in whose territory it is carried out – in Bulgaria those should be officers from the Bulgarian State Agency Technical Operations/SATO); 4. conditions under which the cross-border surveillance will be carried out; 5. the term of carrying out the cross-border surveillance. The Chairman or an authorized deputy - chairman of the Sofia City Court immediately gives written permission – if he/she finds the request reasonable, for the cross-border surveillance to be carried out or refuses to permit the measure, giving reasons for the refusal. The permission is sent through the Supreme Cassation Prosecutor's Office to the competent authorities of the requesting state, of which the competent Bulgarian authorities are also notified.
In urgent cases, when no prior authorization has been requested, the surveillance from the foreign officials may continue in the territory of Bulgaria upon immediate notification of the Bulgarian Supreme Prosecutor's Office of Cassation and the Chief Secretary of the Bulgarian Ministry of Interior that the border was crossed during the surveillance. Following the notification, the Supreme Cassation Prosecutor's Office immediately decides whether the surveillance should be terminated and notifies the requesting state and the Chief Secretary of the Bulgarian Ministry of Interior. The requesting state should immediately send a request for legal assistance via cross border surveillance to the Supreme Prosecutor's Office of Cassation, in which amongst the information from 1-5, circumstances that determine the need for urgency and crossing the border without prior permission are explained and motivated. The Supreme Prosecutor's Office of Cassation rules immediately on the acceptance of the request and, if it grants it, immediately submits a written reasoned request for permission to the Chairman or to an authorized deputy - chairman of the Sofia City Court. In case the Supreme Prosecutor's Office of Cassation refuses to accept the request the surveillance should be cancelled immediately. The Chairman or an authorized deputy - chairman of the Sofia City Court within five hours - after the Bulgarian border has been crossed, gives written permission – if he/she finds the request reasonable, for the cross-border surveillance to be carried out or refuses to permit the measure, giving reasons for the refusal. In case of a refusal the surveillance should be cancelled.