An intercepted email in France, a frozen bank account in Curacao, a decrypted cell phone in the United States, a statement taken in Caracas. In today's transnational economic crime, it is exceptional for all the evidence in a trial to be generated within the borders of the prosecuting country. The rule today is fragmented evidence: produced in various jurisdictions, under different standards of due process, and later transferred to the trial through instruments of international judicial cooperation.

This fragmentation raises a question that determines entire proceedings: under which law is the validity of evidence produced outside the country of trial examined? That of the place where it was obtained, or that of the country where it is used? This study analyzes how three legal systems with which VENFORT Abogados routinely works—Spain, the United States, and Venezuela—answer that question, and what the practical implications are for defense strategy in investigations involving white-collar crime, transnational corruption, and money laundering.

The general framework: international judicial cooperation and its instruments

No State can, on its own, investigate beyond its borders. When the relevant evidence is in another country —bank records, corporate emails, witnesses, expert reports—, the only legitimate way to obtain it is the mutual legal assistancea State formally requests another to carry out a procedural act and transmit the result, in accordance with a bilateral or multilateral treaty that both have ratified.

The most relevant instruments in the practice of the three countries we analyze are:

The Treaty on Mutual Legal Assistance in Criminal Matters between the Kingdom of Spain and the United States of America, signed in Washington on November 20, 1990, in force since June 30, 1993 (BOE of June 17, 1993), supplemented in 2004 by an additional instrument incorporating the Mutual Legal Assistance Agreement between the European Union and the United States of June 25, 2003.

The European Convention on Mutual Assistance in Criminal Matters, done in Strasbourg on April 20, 1959, ratified by Spain in 1982, with its Additional Protocol of 1978 and its Second Additional Protocol of 2001 —the latter in force for Spain since July 1, 2018—, which substantially expanded cooperation mechanisms, including videoconferencing and joint investigation teams.

The Inter-American Convention on Mutual Assistance in Criminal Matters, adopted in Nassau on May 23, 1992, to which Venezuela has been a State Party since 1996, and which is applicable among American countries.

The Agreement on Mutual Legal Assistance in Criminal Matters between Venezuela and the United States, signed in Caracas on October 12, 1997, a specific framework under which both countries have historically cooperated in investigations into corruption, drug trafficking, and financial crimes with transnational elements.

It is worth noting a relevant fact for any family or executive with simultaneous interests in Spain and Venezuela: There is no bilateral treaty on mutual legal assistance in criminal matters between the two countries.. The only bilateral instrument currently in force is the Caracas Extradition Treaty of January 4, 1989, which governs exclusively the surrender of requested persons, not the exchange of evidence. In practice, this gap necessitates resorting to ordinary diplomatic channels, the United Nations Convention against Transnational Organized Crime (the Palermo Convention, to the extent it is applicable), or case-by-case reciprocity mechanisms, which introduces delays and uncertainties that a well-prepared defense must anticipate from the outset.

Spain: The Principle of Non-Inquiry with Limits

Over the past twenty years, the case law of the Second Chamber of the Supreme Court has established a relatively stable doctrine regarding evidence obtained abroad: the so-called principle of non-inquiry. Pursuant to this doctrine, Spanish courts are not required to verify that investigative proceedings conducted in another country complied point-by-point with the Spanish Criminal Prosecution Act, because demanding such strict compliance would render any international judicial cooperation practically unfeasible.

That principle, however, does not equate to uncritical acceptance. The Supreme Court Ruling No. 116/2017, dated February 23 —issued in connection with what is known as the «Falciani list,» concerning bank data stolen by a private individual in Switzerland and subsequently used by Spanish tax authorities—established the standard that continues to govern this matter today: the Spanish court does not apply a strict «double compliance» test under Spanish law, but neither can it remain indifferent to flagrant violations of the fundamental structural rights of the proceedings. The standard of review focuses on the essential principles of the proceedings—who obtained the evidence, what role public authorities played, and whether there was a substantial violation of procedural safeguards—rather than on a formal comparison of procedures.

This doctrinal approach has been projected with special intensity onto transnational digital evidence in recent years, regarding encrypted communications obtained through the interception of encrypted messaging servers operated outside Spain (the well-known EncroChat phenomenon), where French and Dutch authorities massively intercepted communications that were later shared with other Member States via a European Investigation Order. The recent jurisprudential trend of the Supreme Court on this matter places the focus of legality control on the correctness of the European Investigation Order issued by the receiving Spanish authority, rather than on the exhaustive detail of the technical procedure executed by the foreign authority, accepting the validity of the action when it meets sufficient standards of equivalent procedural guarantee.

For the chain of custody of digital and banking evidence obtained abroad, Spanish practice requires, at a minimum: clear identification of the foreign authority that produced the evidence, documentary evidence of the request for judicial assistance that was filed, certification of the integrity of the data submitted (cryptographic hash in the case of digital media), and, whenever possible, the appearance or statement of the foreign official who conducted the proceedings, for the purpose of cross-examination.

United States: The Constitutional Problem of «State Action»

The U.S. system approaches the issue from a different angle, shaped by the constitutional nature of its due process guarantees. The Fourth Amendment—which protects against unreasonable searches and seizures—does not, as a general rule, apply to the actions of foreign authorities operating without substantial involvement by U.S. agents, because there is no «state action» attributable to the United States. This is the principle established by the U.S. Supreme Court in United States v. Verdugo-Urquidez, 494 U.S. 259 (1990).

The relevant exception is the one known as «"joint venture doctrine"»: When U.S. federal agents actively and substantially participate in a joint operation with foreign authorities—not merely as observers, but as co-leaders of the operation—the evidence obtained is subject to a minimum standard of reasonableness known as «"shocks the conscience"» (a test originally derived from Rochin v. California, 342 U.S. 165 (1952), which is significantly more lenient than the standard of probable cause required for purely domestic proceedings. The Ninth Circuit Court of Appeals codified this doctrine in United States v. Barona, 56 F.3d 1087 (9th Cir. 1995), a leading case on this subject.

In terms of formal admissibility, the Federal Rules of Evidence (Federal Rules of Evidence) provide for self-authentication mechanisms for certified foreign documents—including commercial and banking records—under Rule 902, in its sections regarding certified commercial records and certified electronic evidence. In transnational corruption investigations under the Foreign Corrupt Practices Act, this mechanism is central: it allows international bank records obtained through mutual legal assistance or international interbank messaging systems to be admitted into the proceedings without the need for an in-person witness, provided they are accompanied by the certification required by the rule itself.

Venezuela: Judicial Cooperation and Judicial Review of Evidence

The Venezuelan criminal procedure system, which has been adversarial in nature since the Organic Code of Criminal Procedure entered into force, assigns to the Public Prosecutor’s Office the responsibility for conducting investigations and requesting international judicial cooperation when relevant evidence is located outside the national territory, through the mutual legal assistance mechanisms provided for in the treaties to which Venezuela is a party—primarily the 1992 Nassau Convention in the inter-American context, and the 1997 bilateral agreement with the United States when cooperation with that country is sought.

The absence of a bilateral treaty on mutual legal assistance in criminal matters with Spain, as noted above, takes on particular practical significance in the increasingly frequent proceedings in which facts with ramifications in both countries are investigated in parallel: without such a specific instrument, cooperation depends on general diplomatic channels or multilateral instruments whose application is more uncertain, which can result in considerably longer delays in obtaining or transferring evidence between the two jurisdictions.

With regard to the internal review of evidence, the Venezuelan Public Prosecutor’s Office and the supervisory courts oversee the legality of evidence admitted into the proceedings, including evidence obtained abroad through letters rogatory, in accordance with the general principles of legality and judicial review of evidence that underpin the Venezuelan criminal justice system. Given the practical importance of this point for any person under investigation with assets in Venezuela, we always recommend verifying the current numbering of the applicable provisions—subject to recent partial amendments—directly with the legal team before basing any procedural strategy on a specific legal reference.

An illustrative scenario: parallel investigations in three jurisdictions

To illustrate how these mechanisms operate in practice—without referring to any specific or identifiable case—let’s consider a common scenario in our professional practice: an investigation into alleged corruption linked to contracts between a Latin American state-owned company and international suppliers, in which authorities from the country of origin, a U.S. federal prosecutor’s office investigating under the Foreign Corrupt Practices Act due to the involvement of U.S. entities and bank accounts, and, eventually, Spanish authorities—due to the location of assets or the residence of one of the individuals under investigation—are all involved simultaneously.

In such a scenario, typical evidence—such as international bank transfers, corporate communications, and statements from protected witnesses—is generated and transferred between jurisdictions through the MLAT instruments described above, and its ultimate validity depends on each link in that chain—production, certification, transfer, and incorporation into the receiving proceeding—complying with the standard of legality applicable in the country where the evidence is ultimately used, in accordance with the criteria set forth in the preceding sections. A serious technical defense audits each of these links independently: who produced the evidence, under what authorization, with what safeguards, and whether the transfer to the destination jurisdiction was carried out in accordance with the applicable cooperation instrument.

Regarding the public allegations of the illegality of the foreign evidence

It is common, in high-profile investigations, for the person under investigation or their associates to publicly claim that evidence from a foreign country is «unlawful» or «politically motivated,» without developing a specific legal analysis of why that would be the case. From a strictly technical perspective, for such a claim to have real procedural viability, it requires identifying with precision the alleged legal defect: was it obtained without the judicial authorization required in the country of origin? Was it carried out in violation of a structural fundamental right of the proceedings? Was the cooperation instrument under which it was transferred to the receiving proceeding the correct one?

The mere circumstance that a piece of evidence originates from a country with which there are diplomatic or political tensions does not make it unlawful in and of itself; and, conversely, the existence of a current cooperation treaty does not automatically cure any defect in its production. The analysis must always be done on a case-by-case basis, grounded in the established jurisprudential criteria, rather than on generalizations. It is precisely in this technical audit, link by link, where it is decided whether a piece of evidence withstands the test of admissibility or if a real ground for exclusion exists.

Frequently asked questions

1. Can evidence obtained by a country that did not strictly follow Spanish procedure be used in Spain? Yes, in principle, pursuant to the principle of non-inquiry, provided there is no flagrant violation of structural fundamental rights. The review focuses on essential guarantees, not on absolute formal compliance with Spanish law.
2. What happens if a US agent participated in a procedure carried out in another country? If their participation was active and substantial, the evidence is subject to the corresponding US constitutional standard («joint venture doctrine»), rather than being governed solely by the law of the country where the investigative act was conducted.
3. Is there direct criminal judicial cooperation between Spain and Venezuela? Not through a specific bilateral mutual legal assistance treaty in criminal matters; only the 1989 Extradition Treaty exists. Evidentiary cooperation depends on other mechanisms, which are generally slower.
4. Is the chain of custody for an email or a wiretapped phone in another country always valid? Not automatically. It requires complete documentation of the request for judicial assistance, certification of data integrity, and, whenever possible, the possibility of contesting the foreign authority's action.
5. Is it enough to claim that the evidence is «political» to exclude it from the proceedings? No. The exclusion of evidence requires identifying a specific and verifiable legal flaw —in production, of guarantee, or of the channel of cooperation—, not a generic disqualification without technical foundation.

Conclusion

Evidence obtained abroad has become the backbone of most transnational economic criminal proceedings. Its validity is not decided at a single point, but at every link in a chain that crosses borders, legal systems, and distinct standard of guarantees. Spain, the United States, and Venezuela share the goal of facilitating international judicial cooperation, but differ significantly in the specific standard of review they apply to that evidence once it arrives at the proceeding.

For anyone facing an investigation of this nature, an effective defense does not consist of wholesale disqualification of foreign evidence, but rather of auditing it with technical precision, jurisdiction by jurisdiction, instrument by instrument. That is precisely the advantage of having a team capable of operating with direct knowledge of all three systems and coordinating the strategy simultaneously rather than in a fragmented manner.

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VENFORT By Aldana & Abogados · Madrid · Caracas · Presence in 15 jurisdictions
White-collar crime · International judicial cooperation · Extradition · Compliance · Corporate lawfare

Alan Aldana

Founding partner and Director of the International Criminal Law Department at VENFORT Lawyers. Lawyer accredited before the International Criminal Court, with over twenty years of practice in extraditions, INTERPOL proceedings, economic criminal law, and international sanctions, assists entrepreneurs, executives, institutions, and families with interests in Europe and the Americas.