The instrument allows for investigative units from other member states to continue in Spain the surveillance measures initiated in the country of investigation. Surveillance is interpreted in the sense of “plain sight”, not allowing to conduct other measures affecting fundamental rights such as using the data obtained in Spanish territory through the installation of tracking devices.
short summary of general requirements for a measure:
A normalized form must be used for the request, and the transmission channels are the usual for international police cooperation (SIRENE Office, Interpol, SIENA). The requests will be handled by the Single Point of Contact and forwarded to the national authority for its authorization.
The request form shall include, when applicable, the identification data of the foreign officers to carry out the surveillance, the license plates of the vehicles used and the registration number of the weapons they carry.
Spain can impose conditions for the execution of the measure. The general rule is that the surveillances are to be conducted by delegation on the Spanish Law Enforcement Authorities, except for bordering countries (France and Portugal) under reciprocity conditions.
CISA only allows for the surveillance in plain sight, and no other restrictive or coercive measures are allowed in absence of other mutual legal assistance instruments. The foreign officers could carry weapons and the use of force is forbidden, except in case of threat to life and integrity of the foreign officers or other persons.
The foreign officers are obliged to report to the national authorities any crime they could detect during the surveillance, using the contact point provided in the issued authorization, which serves as a justification of their presence in national territory in official mission.
After each cross-border surveillance operation a report has to be produced, as a final one as the authorization term expires, even if the operation was not successful.