Sin categoríaInternational letters rogatory: how judicial cooperation in criminal matters works between countries

Crime rarely respects borders. A fraud committed from a server abroad, a laundering network with accounts in several countries or a witness residing outside Spain are everyday situations in modern criminal investigations. When this happens, the Spanish judge or prosecutor cannot simply send the police to another country: they need to activate a mechanism of international judicial cooperation. The classic instrument for this is the letter rogatory, a century-old institution that remains, despite the new European tools, the usual channel of judicial assistance with countries outside the European Union.

What a letter rogatory is

A letter rogatory is the formal request that a judicial authority of one State addresses to the competent authority of another State so that it will carry out, in its territory, a procedural act that the former cannot execute by itself: taking a witness statement, serving a summons, conducting a search, seizing assets, obtaining banking documentation or forwarding criminal records. The rationale is simple: each State’s judicial sovereignty is limited to its own territory, so any measure to be carried out in another country requires the collaboration of that country’s own courts or authorities.

The applicable legal framework

In Spain, the legal basis is found in Articles 277 et seq. of the Criminal Procedure Act, which govern international judicial assistance. To this are added the multilateral conventions signed by Spain, most notably the Council of Europe’s European Convention on Mutual Assistance in Criminal Matters of 1959 and its additional protocols, as well as numerous bilateral treaties with countries of Latin America, the United States and North Africa. Where no convention applies, the principle of reciprocity governs: Spain provides assistance expecting the other State to do the same when the occasion arises.

Key points of the letter rogatory:

• It must always be issued or authorised by a judicial authority, never by the police alone.
• It is normally processed through the Ministry of Justice or, where applicable, directly between judicial authorities when the convention allows it.
• Within the European Union, the European Investigation Order has largely replaced the classic letter rogatory, speeding up the process.
• Evidence obtained abroad must respect both the law of the requested country and the safeguards of Spanish criminal procedure.

How it is processed in practice

The usual procedure begins when the investigating judge or the prosecutor considers necessary a measure that can only be carried out in another country. The request is drafted, identifying precisely the object of the petition, the facts under investigation and the specific assistance required. Where an international convention so allows, the letter rogatory can be sent directly between judicial authorities or through the central authorities designated in each treaty, normally the Ministry of Justice. In the absence of a treaty channel, the slower diplomatic route is used, involving the Ministry of Foreign Affairs and the Spanish diplomatic representation in the requested country. Once received, the authority of the requested State examines the request under its own procedural law, decides whether to execute it and sends the result back to Spain. This process can take months, especially where the requested country demands additional formal requirements, official translation or verification of the double criminality of the fact under investigation.

The European Investigation Order: the evolution within the EU

Between the Member States of the European Union, Directive 2014/41/EU introduced the European Investigation Order, incorporated into Spanish law by Law 3/2018. For virtually all evidentiary measures, this instrument replaces the traditional letter rogatory, on the basis of the principle of mutual recognition: the executing authority must, save for strictly defined grounds of refusal, recognise and execute the order as if it were its own, with much shorter time limits and standardised forms. This has meant a notable acceleration in cases with cross-border elements within the European area, compared with the slowness traditionally associated with the classic letter rogatory.

Safeguards, limits and validity of the evidence

Not every request is executed automatically. Requested States may refuse cooperation where the act requested would infringe their public policy or fundamental rights recognised in their legal system, or where the fact under investigation would not be an offence under their own law (double criminality), a customary requirement for certain more invasive measures such as searches or the interception of communications. In addition, evidence obtained through a letter rogatory must be incorporated into the Spanish proceedings respecting the guarantees of adversarial proceedings and the right of defence: the accused must be able to know the content of the measure carried out abroad and, where appropriate, challenge it. A recurring problem in forensic practice is the lack of certainty about how the measure was carried out abroad, what safeguards surrounded the taking of a statement or the seizure of a device, and whether the result can be incorporated without breaking the chain of custody. Spanish courts require the requesting authority to verify, as far as possible, that the action met minimum standards of reliability, and that the translation of the documentation sent is faithful.

An indispensable instrument despite its limitations

The globalisation of economic crime, cybercrime and drug trafficking has multiplied the use of international judicial cooperation. Despite criticism of its slowness and the disparity of criteria between States, the letter rogatory remains, outside the European sphere, the essential tool for the Spanish criminal justice system to obtain evidence, serve decisions or recover assets located beyond our borders. Knowing its time limits, requirements and limits is indispensable both for those driving an investigation and for those who must defend against evidence obtained abroad.

Related: the European arrest warrant, INTERPOL red notices and defence before the Audiencia Nacional.