The recent appointment of forensic psychiatrist Dr. Pau Pérez-Sales as United Nations special rapporteur on torture and other cruel, inhuman or degrading treatment or punishment – the first non-lawyer to hold the mandate – marks a notable moment in the continuing evolution of international efforts to prevent all forms of ill-treatment. It also coincides with the fifth anniversary of the launch of the Principles on Effective Interviewing for Investigations and Information Gathering, an international instrument designed to bring different professional perspectives together through a common framework for reducing the use of torture in interrogations. Pérez-Sales, whose groundbreaking scholarship on psychological torture has fundamentally shaped the field, played a central role in the collective development of the Principles. Now, five years later, it seems an opportune time to assess how implementation has progressed.
Implementation of the instrument, known as the Méndez Principles, is underway across many regions, institutions, and professional communities, and they have been translated into 24 languages. They are advancing via multiple routes, including legal monitoring, scientific research, professional training, institutional development, technological innovation, and international collaboration.
One recent illustration comes from Guatemala, where the newly appointed prosecutor general requested support from the Organization of American States to explore the Méndez Principles and develop capacity-building initiatives for prosecutors, investigators, and courts. While still at an early stage, this initiative reflects the continuing expansion of interest in the Principles across new institutional and geographic contexts. (The Guatemalan authorities have secured the participation of one of us, the eponymous Professor Juan E. Méndez, who as U.N. Special Rapporteur on torture issued the 2016 appeal that spurred the development of the Principles. The other author, Steven J. Barela, served as editor of the Principles and has been closely involved in their dissemination and implementation.) The examples that follow demonstrate the different channels through which effective interviewing is taking shape in practice.
The diversity of pathways is no accident. During the drafting of the Principles themselves, experts from law, science, human rights, and professional practice approached the project with different priorities and ways of thinking. Rather than eliminating those differences, the Principles established a shared standard through which they could contribute to a common objective. While the efforts differ substantially in form and context, each contributes to the shared task of translating the Principles into practice.
How state authorities can legitimately obtain information from individuals has challenged legal and moral thinkers for centuries. One notable example is Jeremy Bentham’s unpublished papers on torture from the early 19th century, which contain what is widely regarded as a precursor to the modern “ticking bomb scenario.” The Méndez Principles answer that enduring question with a central proposition: the collection of accurate information and respect for human rights are not competing objectives — they are mutually reinforcing. Simply put, research shows that building rapport works. Torture does not.
Although not legally binding, the Principles have increasingly emerged as a soft-law instrument influencing policy, professional practice, training, and institutional reform. At a time marked by the erosion of human rights commitments, growing challenges to procedural safeguards, and an increasing strain on the international rules-based order, it is significant that the Méndez Principles are advancing by appealing simultaneously through the diverse languages of law, science, and ethics. Their distinct arguments create multiple avenues for implementation, allowing progress to continue even when certain political or institutional pathways become constricted.
These various perspectives contribute to the growing relevance and resilience of the Principles; they also help explain the uneven nature of their implementation. This will be a central challenge for the next phase: how can professionals from different fields reinforce one another without drifting into separate and disconnected communities of practice?
Emblematic Cases
United States – From Science to Professional Standards
Established in 2010 in response to the failures of a torture program, the U.S. High-Value Detainee Interrogation Group (HIG) has supported a substantial body of research on effective interviewing that helped inform the scientific foundations later reflected in the Méndez Principles. Among the most influential contributions has been the ORBIT model, validated through the analysis of more than 2,000 hours of real-world interviews across multiple contexts and consistently associated with improved engagement and information yield. All of this work together has helped establish science-based interviewing as an emerging training standard for law enforcement.
California’s approach is particularly noteworthy because it seeks to eliminate unscientific interviewing practices through training standards and professional regulation. In 2024, the state’s Commission on Peace Officer Standards and Training (POST) issued guidance for certified interviewing programs to demonstrate an empirical basis and show that they are not teaching methods associated with false confessions. The standards also prohibit threats, physical harm, deception, and psychologically manipulative tactics. These reforms have accelerated adoption of science-based interviewing across the state, with more than 5,500 officers trained during the past three years – marginalizing training providers that continue to promote unscientific methods. This model is increasingly attracting attention elsewhere in the United States because it seeks to change interviewing culture through professional standards embraced by the law enforcement community itself.
The human stakes of such reforms were vividly illustrated when Denise Huskins and Aaron Quinn — the victims whose wrongful treatment by police after a home invasion and kidnapping was chronicled in the documentary American Nightmare — spoke to practitioners at the 2025 conference on science-based interviewing. Describing how coercive and assumption-driven interviewing led investigators to treat them as suspects rather than victims, they offer a powerful reminder that miscarriages of justice often become the catalyst for change. In the following year, the offender was re-interviewed by an investigator trained in science-based interviewing (ORBIT), resulting in admissions to four additional offences.
Ukraine – Extraordinary Circumstances
Ukraine illustrates how implementation can continue even during armed conflict. Engagement with science-based investigative interviewing began several years before the release of the Méndez Principles, but attitudes toward these approaches have changed significantly over time. What was initially viewed by some as a foreign concept gradually came to be seen as a strategic choice about the future of criminal justice. Russia’s full-scale invasion in 2022 did not halt this process. Rather, it underscored the need for reliable, rights-compliant methods of obtaining information in the investigation of war crimes and other serious offences.
Ukraine has developed a growing community of trainers and practitioners promoting investigative interviewing across the justice sector. What began primarily as training initiatives has increasingly evolved into broader efforts at institutional reform. Approaches reflected in the Méndez Principles are now appearing in prosecutorial training programs, strategic discussions on torture prevention and child-friendly justice, professional ethics frameworks, and university curricula, reflecting a growing recognition that long-term reform depends on educating the next generation of professionals. Efforts are also underway to develop practical guidance for investigators and prosecutors, as well as national protocols for interviewing children during criminal proceedings.
Thailand – Domestic Leadership
Thailand provides an example of implementation advancing through domestic leadership and institutional partnerships. Under the guidance of the Office of the Attorney General and Senior Public Prosecutor Santanee Ditsayabut, Thai practitioners and institutions have worked to promote ethical, information-gathering approaches to interviewing through training, policy development, and professional cooperation. This work has brought together the Thailand Institute of Justice (TIJ), the Department of Special Investigation (DSI), the Office of the Attorney General, the National Human Rights Commission of Thailand, and other national institutions, supported by collaboration with international partners (APT, NCHR, NZ Police). These efforts also build upon a broader tradition of criminal justice reform in Thailand associated with the late Princess Bajrakitiyabha, whose work helped strengthen procedural safeguards and access to justice and established Thailand as an important voice in international criminal justice and human rights reform.
Recent developments in Thailand’s criminal procedure framework have strengthened the legal foundations for rights-compliant interviewing through provisions addressing legal assistance (§134/1), notification of rights (§134/4), recording (§134/4), and prohibitions on coercive questioning practices (§135). Implementation remains an ongoing challenge, but the legal framework provides an important foundation for reform.
Reform efforts have continued to expand despite longstanding institutional habits that favor confession-oriented approaches. Increasing attention is now being given to professional interviewing skills, recording practices, legal safeguards, and the reliability of information obtained during investigations. These developments suggest a broader cultural shift within parts of the justice sector toward approaches that view effectiveness and rights protection as mutually reinforcing rather than competing objectives.
Brazil – Large-Scale Implementation
Implementation efforts have advanced in Brazil through a growing network of scientific, professional, and institutional partnerships. A central role has been played by CogJus (Laboratory of Teaching and Research in Cognition and Justice), an academic and NGO research group at Atitus Educação in the southern State of Rio Grande do Sul, working together with police academies, the Ministry of Justice, and international partners. Through these collaborations, evidence-based approaches to interviewing have been incorporated into training, curriculum development, instructor networks, and evaluation frameworks across much of the country.
As reflected in CogJus’s Impact Reports (2023, 2024, 2025), these efforts have reached more than 16,000 professionals and extended to 24 states, making Brazil the site of one of the largest and most ambitious implementation efforts currently underway. This growth has been supported by an emerging national implementation infrastructure that includes a network of 52 instructor-supervisors, multi-level training programs, instructor supervision mechanisms, and standardized assessment tools.
Complementing these developments, the publication of the CogJus Investigative Interviewing Manual has helped make scientific research and practical guidance more accessible to practitioners in Portuguese. Together, these developments illustrate how the Méndez Principles can currently advance more rapidly through scientific and professional pathways, while legal and policy dimensions progress at a different pace. This evolving landscape also highlights the importance of ensuring that the different dimensions and priorities of implementation remain connected.
The Emergence of the Méndez Principles as a Soft-Law Instrument
One significant development related to the Méndez Principles in the past five years has been their growing emergence as a non-binding legal instrument of international human rights law. Instruments of this kind can play an important role in clarifying and guiding the implementation of international legal obligations. Evidence of this trend can be seen in the increasing number of international, regional, and domestic bodies that have endorsed, referenced, and applied the Principles in their work.
At its launch in June 2021, the document received the enthusiastic support of then-U.N. High Commissioner for Human Rights Michele Bachelet, former president of Chile. Since then, the U.N. Committee Against Torture has regularly cited the Principles in their observations for country visits (e.g., here at §12(b), here at §33, and here at §16(c)). In response to such statements by treaty bodies, Sweden aims to adopt the Principles as official policy and is proceeding towards implementation. The U.N. Subcommittee on Prevention of Torture (p. 11, §54) has welcomed the Principles as an essential step in a cultural shift for the criminal justice process. The U.N. Manual on Human Rights for Law Enforcement Officials (Chp 8, p. 23 ff) cites them as a part of human rights standards and a framework for application. And the U.N. Manual on Investigative Interviewing for Criminal Investigation released in 2024 further confirms and authenticates the value of the approach.
The Council of Europe’s Committee for the Prevention of Torture frequently cites the Principles in annual reports, in decisions on specific cases, and in reports emanating from their visits to member countries (e.g., here, here and here). In October 2023, the General Assembly of the Organization of American States (p. 141) welcomed the Principles and recommended adoption by all member States in the Western Hemisphere (while recording a reservation by the United States). In the same year, the African Commission on Human and Peoples’ Rights likewise adopted a resolution welcoming the Méndez Principles and encouraging their use by member States.
In December 2022, the U.N. General Assembly adopted two resolutions (one on prevention and eradication of torture and the other on the administration of justice) that encouraged States to apply and implement the ideas embodied in the Principles. This continued in 2025, when the General Assembly took note with appreciation of the Méndez Principles and encouraged States to use them through the implementation of non-coercive interviewing methods and procedural safeguards, thereby “operationalizing the presumption of innocence.” Such language is particularly noteworthy because it links the Principles not only to the prevention of torture and ill-treatment, but also to one of the foundational guarantees of criminal justice.
The highest courts of some countries have cited the Principles. A concurring opinion by the Supreme Federal Tribunal of Brazil — striking down a conviction that violated the exclusionary rule in the Convention Against Torture — referred the Principles to the courts below as a means to determine whether evidence had been obtained unlawfully. The appellate panel of Colombia’s Special Jurisdiction for Peace rejected a lower panel’s refusal to deny the benefit of reduced penalty to a woman who had applied for it and remanded the case with instructions to the admissions panel to interview her in accordance with the Principles.
Instruments of this sort—often referred to as “soft law”—are especially important in the international law of human rights because binding instruments are necessarily broad and even abstract. This remains true even for universal norms such as the prohibition of torture. Binding standards, when applied to specific cases, usually need to be interpreted with the assistance of soft law standards.
To be sure, not every instrument published outside treaty law becomes a highly influential instrument, even if non-binding. They do so when they are backed by science and research and by the practice of States and international organs in applying them. The Méndez Principles are already well along that trajectory. In the first place, they reflect decades of existing practice in several States and corresponding scientific research. In addition, they provide courts, prosecutors and defense attorneys with an objective standard by which to determine whether confessions and other expressions against interest, as well as statements by witnesses and victims, should be admitted into evidence because safeguards against coercive methods have indeed been observed. Significantly, the adoption by police academies and in programs of bilateral and multilateral capacity-building efforts demonstrate that the Principles are considered the professional standard that all investigatory interviews should meet if they are guided by the objectives of establishing the truth, operationalizing the presumption of innocence and strengthening the rule of law.
Infrastructure for Change
The Council of Europe’s Committee for the Prevention of Torture (CPT)
The above-noted engagement with the Principles by the Council of Europe’s Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT) has helped build the institutional infrastructure for implementation through increasing references to the Principles as the body encourages a broader shift from confession-driven investigations toward evidence-based interviewing. In reports concerning Serbia, North Macedonia, Cyprus, Luxembourg and other jurisdictions, the CPT has emphasized the value of professional investigative interviewing, audio-video recording, and robust procedural safeguards. This approach provides a practical framework for assessing how safeguards operate in custodial settings.
At the same time, CPT monitoring illustrates an important reality of implementation: progress often occurs alongside persistent shortcomings in practice. Unannounced visits to places of custody continue to reveal problems such as delayed access to lawyers and doctors, failures to notify third parties of custody, inadequate recording, insufficient protection of vulnerable persons, weaknesses in oversight and accountability, and wide use of informal questioning outside procedural standards. This work demonstrates that effective interviewing cannot be assessed by interviewing methods alone or by legal safeguards alone. Rather, implementation requires examining how scientific foundations, procedural safeguards, and preventive objectives interact in practice.
Recording, Research, and Reform
Another important dimension of the infrastructure supporting implementation of the Principles is in the growing emphasis on systems for recording and documenting interviews. Recording has long served as an important safeguard against coercion and abuse, but its significance extends beyond accountability alone. The adoption of required recording made possible some of the most influential scientific advances in interviewing. From the scientific evaluation of PEACE-based interviewing approaches to the large-scale coding and analysis of interviews with terrorism suspects and other serious offenders through ORBIT, recording has enabled researchers to study interviewing practices with a level of rigor that was previously impossible. In this sense, recording helped create the scientific foundations upon which many of the general principles of effective interviewing now rest.
The challenge today is not simply whether interviews are recorded, but how they are recorded, managed, accessed, and preserved. A legal requirement to record is not, by itself, sufficient. Without clear technical and procedural standards, recordings may fail to provide a complete, reliable, and transparent account of what occurred. Advances in digital recording, evidence management, chain-of-custody documentation, secure storage, and remote access are reshaping how interviews are conducted, reviewed, and relied upon in practice. Increasing attention should therefore be given to the development of common standards and infrastructure capable of protecting victims, witnesses, suspects, and investigators while supporting transparency, accountability, evidential integrity, and public trust. In this respect, implementation of the Méndez Principles is advancing through law, policy, and training, as well as through the practical systems that document and preserve the interview process itself.
European Research Council: JUSTICE
Scientific infrastructure is likewise expanding through the launch last month of the European Research Council Synergy project JUSTICE (Joining Unique Strategies Together for Interrogative Coercion Elimination). It is a six-year, €10.4 million interdisciplinary initiative bringing together researchers from law, psychology, neuroscience, policing studies, data science, and artificial intelligence. Grounded in the Méndez Principles, the project seeks to understand why coercive interviewing practices persist despite decades of reform efforts and how they can be replaced with effective, ethical, and evidence-based alternatives. Among its ambitious objectives is the development of an AI-supported “Méndez LLM” intended to reinforce ethical and evidence-based interviewing.
The project is particularly noteworthy because it brings into technological form many of the same challenges that arose during the drafting of the Principles themselves and that continue to emerge in implementation efforts today: how to integrate distinct disciplinary logics, professional practices, scientific evidence, and legal safeguards into a coherent structure without losing the insights of any one community. In this sense, JUSTICE illustrates how the questions that shaped the creation of the Méndez Principles continue to evolve as implementation advances into new technological and institutional domains.
The Design at Work
One Standard, Different Reasons
Taken together, these developments point to a broader pattern. Different communities have found different reasons to embrace the Principles. Human rights advocates may be drawn to the legal safeguards framework and preventive function of the Principles, empirical researchers and practitioners to their emphasis on effectiveness, professionalism, and reliable information. These varying perspectives reflect the professional logic and institutional responsibilities of each community. Empirical research and training initiatives often frame the challenge in terms of rapport, mindset, and methods of questioning. Law-based monitoring bodies, by contrast, tend to emphasize safeguards such as access to counsel, medical examination, oversight, and accountability. These perspectives are not contradictory. Rather, they represent different pathways toward effective, fair, and rights-compliant interviewing.
This should not come as a surprise. The challenge of bringing together different professional communities was present during the drafting of the Principles themselves. The experts involved often approached the project through different disciplinary logics and priorities. The achievement of the drafting process was not the discounting or removal of those differences, but the deliberate creation of a framework through which these communities could remain distinct while working toward a common objective. Similar debate and discussion are bound to arise in translating an interdisciplinary framework into diverse institutional settings.
The experience of the Istanbul Protocol, the 1999 standard recognized by the U.N. for the effective investigation and documentation of torture and ill-treatment, offers a useful comparison. Over more than two decades, implementation efforts demonstrated the obstacles of translating an international standard into diverse settings. The 2022 revision of the Protocol added a chapter on implementation, which observed that it need not unfold through an orchestrated sequence of assessment, capacity-building, and policy reform. Progress often depends on recognizing opportunities as they arise and on building relationships across communities. As Vincent Iacopino, who played a central role in the development and revision of the Istanbul Protocol, reflected in a recent research interview with one of us (Barela): “It’s not just about the principles that you carry in your bag … it’s about the personal interactions you have and the trust building – the partnerships that you form.”
This lesson resonates strongly for the Méndez Principles. The experience of the Istanbul Protocol suggests that implementation need not begin from a single point of origin or follow a predetermined sequence. Different communities will engage with the Principles for different reasons and at different moments, yet their efforts can still reinforce one another.
Integration of Legal Safeguards
Keeping these different perspectives connected requires conscious effort and continued dialogue. A 2025 statement by Steering Committee co-chairs Juan E. Méndez and Mark Thomson argued that legal safeguards are not an external limitation on effective interviewing, but “an integral part” of it. In response, the ImpleMéndez COST Action group (more on that below) and the Geneva Academy of International Humanitarian Law and Human Rights co-organized a meeting in Geneva to discuss the issue. One theme that emerged was that safeguards are often understood and expressed differently across disciplines – as legal rights and obligations, operational procedures, or preventive measures – but that these differences should not be mistaken for contradictions. Indeed, some degree of productive friction may be essential to preserving the distinct contributions of different disciplines while maintaining the shared standard established by the Principles.
This dynamic is particularly significant in the current environment. At a moment when human rights institutions and norms face mounting political and financial pressures, and when their future appears increasingly uncertain, many within the human rights community find themselves defending principles that only recently seemed more firmly established. Implementation efforts based on effectiveness, professionalism, and reliable information are increasingly finding receptive audiences in contexts where human rights arguments alone encounter greater political resistance. Yet, many of the values now being advanced through scientific and professional rationales were first articulated and defended through decades of human rights work. Building trust across disciplines therefore requires not only demonstrating the effectiveness of the Principles, but also recognizing the legal safeguards, normative commitments, and human rights foundations that helped bring the document into existence.
Méndez Centres
One promising institutional response to this challenge is the emerging network of Méndez Centres established under the ImpleMéndez COST Action – funded by the European Union to support interdisciplinary networking across the continent. Following the launch of the first centers in Norway and Ireland in 2024, additional centers have since been established in the Dutch-speaking community, the Asia-Pacific region, and soon for German-speaking countries (ZEFAB). In addition to being training providers, these centers serve as institutional hubs bringing together researchers, practitioners, policymakers, and educators to support implementation of the Méndez Principles in local contexts while remaining connected through an international network. Their activities include practitioner engagement, research, resource development, public outreach, and cross-border collaboration, with many of these activities still in their early stages.
As this network continues to develop, it may offer a durable response to a recurring implementation challenge: how to maintain meaningful connections across the scientific, professional, legal, and human rights communities engaged in this work. Enduring implementation depends not only on standards and training, but also on institutions capable of sustaining dialogue, collaboration, and mutual learning over time.
Conclusion
The examples discussed here illustrate a lesson familiar to both researchers and practitioners: translating standards into practice depends on more than the quality of the ideas themselves. Leadership, legislation, institutional commitment, training, research, professional networks, and technological innovation all shape whether reform efforts succeed or stall. Ultimately, enduring implementation depends not only on changing policies and procedures, but also on changing hearts and minds.
Five years of implementation suggest that the real question is no longer whether different communities will embrace the Principles. They increasingly do so – and for different reasons. The task now is to ensure that these communities remain connected in dialogue, preserving their distinct perspectives while recognizing and reinforcing each other’s contributions. The same challenge lay at the heart of the Principles’ original development and remains inherent to their continued evolution.
(Acknowledgment: This article benefited from the generous assistance of colleagues across the Méndez Principles community who shared updates, documentation, and reflections on implementation efforts around the world. The authors are deeply grateful for their contributions, including those of many members of the ImpleMéndez COST Action (CA22128), supported by European Cooperation in Science and Technology.)
