Bilateral or multilateral criminal investigations and the need to gather evidence abroad is nowadays more and more frequent. However, it is a complex process because of the diversity of legal instruments in force in Spain. To solve the existing problems, it is crucial to develop legislation establishing common rules to issue and execute letters of requests in pursuing of transborder evidence. This new legislation should clearly specify the role of the different legal operators that participate in criminal investigations, judges, public prosecutors and legal clerks, as well as the role of the Ministry of Justice as Central Authority. The multiple international conventions in force in Spain include provisions to request that any evidence obtained abroad be gathered following Spanish procedural formalities required under the Spanish law and jurisprudence to be admissible as evidence. The new legislation should include as an obligation that any Spanish request to other countries incorporate the description of the requirements for the requested evidence to be admissible in Spain. Likewise, it should specify how the parties in the case can participate in the issuing and in the execution procedures. The new legislation should also address the setting up of Joint Investigation Teams, granting full authority for its constitution to the investigating judge and modifying the current law that requires for its establishment an authorization from the Ministry of Justice. Equally, the role of the Spanish public prosecutors in these joint investigation teams should be similar to the role described to them in the Spanish criminal procedures rules. Recent legislation (Law 16/2015), does not describe with sufficient clarity the role of liaison magistrates and of the networks on international cooperation in criminal matters. It is necessary a more detailed regulation to incorporate these legal operators that can efficiently facilitate transborder evidence gathering. Similarly, the new legislation should also describe more clearly the powers granted to the Spanish National Member at Eurojust, specifically those related to criminal investigations initiated by another Member State, to the access to Eurojust of the Spanish investigating judge in national investigations and how information of Eurojust investigations are given to the defense counsel..
