Dual criminality is required. A request for ordering and performing the investigative measure shall comprise a copy, a certified copy or a photostat copy of the order of the competent authority. If this is not a court order, the authority requesting judicial assistance shall present a statement explaining that the prerequisites required for such measures are met under the law applicable in the requesting State.
Investigative measures may only be ordered for such a future period of time that is likely to be required in order to fulfill the purpose. Another order is admissible in every case, whenever it is to be expected on account of certain facts that the further performance of an investigative measure will lead to success. Moreover, the investigative measure shall be ended as soon as its requirements have ceased to apply.
Orders and court authorizations for the confiscation of letters shall indicate the designation of the proceedings, the name of the accused, the offence of which the accused is suspected and its statutory designation, as well as the facts from which it results that the order or the authorization is required and proportional in order to clear up the offence.
There shall be compliance with a request for judicial assistance which requires a procedure that differs from Austrian laws on criminal procedure, if this is compatible with the criminal procedure and its principles.