23.07.21
Blog

The Mendez Principles: solving crime with humane interrogation techniques

Torture takes place in a variety of settings, but it is most frequent during interrogation, as Juan Mendez, former United Nations Special Rapporteur on Torture, knows from experience. Aware that too often States only pay lip service to the absolute prohibition of this practice, the Argentine lawyer and the Association for the Prevention of Torture (APT), embark on an ambitious project in 2016: to design a practical alternative to coercive interrogation. The Principles on Effective Interviewing for Investigations and Information Gathering – also known as the Mendez Principles – are launched in June 2021. Interview with Juan Mendez and Barbara Bernath, Secretary General of the Geneva-based APT.

Why does society need these principles?

JM – Despite the very clear and absolutely binding prohibition in international and domestic law, torture has been quite difficult to eradicate because it is widely considered an essential tool for investigators and law enforcement bodies, to elicit confessions or information to solve crimes. This is the case, implicitly, for many State authorities but also for broad segments of public opinion, even in democratic countries.

This despite research showing that the information obtained through illegal means is not always reliable. Hardened criminals can beat the system by providing false information. Persons willing to cooperate provide information that they believe will make torture stop, whether that information is correct or not. Torture is counter-productive to the professional pursuit of the truth because the information elicited very often sends law enforcement personnel on wild goose chases, thereby squandering resources.

We have ample scientific evidence that there are methods of interviewing suspects, victims and witnesses that are both strictly compliant with international human rights norms and avoid all these pitfalls. These methods are not only more ethical, more professional and legal; they have also proven to be more effective in solving crime. Not coincidentally, they are in place in countries that can also boast transparent and accountable institutions, humane prison conditions, and lower crime rates than most of the rest of the world.

What motivated you to look for alternative methods of interrogation?

JM – It became apparent to me that prohibiting torture as a matter of law had not been enough to prevent it. We needed to counter this “naturalization” of the practice in the culture of institutions and in public opinion, which often accepts torture as a “lesser evil” in the face of terrorism, criminality and rising perceptions of insecurity. This is why we felt the need to offer a viable alternative, more humane and ethical, and thus strictly legal, but also more effective in obtaining the truth and solving crimes.

Our Principles on Effective Interviewing are backed by very solid scientific research from various disciplines: criminology, forensic psychology, medicine and neuroscience and, of course, criminal law and procedure, and international human rights law. Most importantly, they are supported by a wealth of professional experience that demonstrates the superior effectiveness of rapport-based interviewing (the creation of a relationship in a short period of time), guided by the pursuit of truth and the operationalization of the presumption of innocence, as opposed to the confession-driven model that so often degenerates into abject forms of human behavior.

What are some of the most important principles in the guidelines?

BB – There are six Mendez Principles that should be taken together. They range from setting the foundations of effective interviewing, in science, law, and ethics, to offering guidance on the practice of interviewing, including for persons in situation of vulnerability, on training, accountability, and implementation. Instead of looking at interviewing in isolation, the Principles consider it as a process starting form the first contact between a person and State authorities. They also uniquely combine a proven methodology based on rapport with the implementation of legal and procedural safeguards.

What does an ideal interview look like?

BB – Preparation and planning are key. The interviewer comes with an open mind, respecting the presumption of innocence rather than with a view to confirm a belief of guilt. In practice, this means that the interviewer’s objective is not to obtain a confession, but accurate and reliable information. This is done through a non-coercive environment, active listening and enabling the interviewee to speak freely, using non-suggestive questions. Legal and procedural safeguards, such as the presence of a lawyer and the audio video recording of the interviewing, ensure an effective outcome. The Principles propose a practical alternative to replace coercive, manipulative and confession-driven interrogation by a more effective and humane interviewing approach.

The guidelines also require that the needs of interviewees who are in situations of vulnerability be identified and addressed. Can you elaborate?

JM - The Principles dedicate a special section to the need to identify vulnerabilities in the interviewee, precisely because the objective of the interview is to obtain voluntary and informed cooperation. In that sense, the Principles not only reassert the prohibition of conduct that instills fear or even terror, but also put the burden on the interviewer to identify those subjective factors that can negatively influence an interviewee’s attitude towards the purpose of the interview.

We were guided by the growing research literature and jurisprudence on how to interview persons with disabilities (even temporary cognitive disabilities), children, women and girls and LGBTQ persons, as well as members of racial, ethnic, religious or national origin minorities. Under the Principles, the interviewer must identify factors that can make their cooperation less than well-informed and strictly voluntary and take steps to eliminate vulnerabilities to the fullest extent possible. This can include the assistance of specialists.

Law enforcement and often society at large strongly believe in the “ticking-bomb scenario”, or even that coercion is part of getting justice for a crime victim. How would you promote the Principles with law enforcement?

BB - There are two elements of response. First, the Principles are based on decades of research from different fields that show that coercion and torture are ineffective in obtaining information in any situation, including in a “ticking bomb” scenario. Science also shows that rapport-based interviewing is more effective in obtaining the truth, even for terrorists or criminals. Justice is better served for all: real perpetrators are sentenced while innocents are protected against forced confessions.

Second, the overall objective of the Principles is both to protect the human rights of the suspects and to improve the outcomes of investigations as well as the professionalism of law enforcement. Throughout the Principles, the benefits for the law enforcement of shifting from interrogation to rapport-based interviewing are underlined. Experience also shows that safeguards, such as audio video recording, protect the police against false accusations of coercion. Stressing the benefits for both society and law enforcement will enable us to move forward on implementation.

We work both with the UN Office of the High Commissioner for Human Rights and the UN Office on Drugs and Crime to promote and disseminate the Principles. The drafting process was supported by UN resolutions. We now aim at endorsement of the Principles, including in a General Assembly resolution. We are promoting them with States and international and regional bodies. In its June/July 2021 session, the European Committee for the Prevention of Torture welcomed the Principles. We also approach professional associations and civil society. We encourage the members of OMCT’s SOS-Torture Network to disseminate the Principles and use them in their work.


The guidelines indicate that a non-coercive interview doesn’t only protect the rights of the accused or detained person but is also important for society at large. How exactly?

JM - Law enforcement and the whole criminal justice system depend heavily on the trust that society places in their operations, their transparency, and their accountability. The only effective way to control crime is for the criminal justice system to enjoy the cooperation of the community. Civic trust is also essential to the normal and efficient functioning of democratic institutions, especially those designed to uphold civil rights and liberties and to protect citizens against arbitrariness and oppression.

That civic trust is profoundly broken when society understands that investigations are generally conducted with the brutality of torture. At the same time, generalized torture places all officers at risk, because the suspect who knows that after apprehension comes horrible pain and suffering will be more likely to resist arrest, often with deadly violence. Most importantly, the practice of torture corrupts the institutions that allow or tolerate it, which has a profoundly negative effect on their ability to serve and protect a society that may fear but does not trust those institutions.

What was the process for developing the Principles?

BB – The process was a long and rich one, involving actors from different fields. Following the 2016 call by Juan Mendez, the APT convened a meeting with a variety of stakeholders that decided to go for an expert driven process. This process was driven by a Steering Committee composed of 15 women and men from different regions whose backgrounds ranged from interviewing to psychology and human rights law and was supported by a large Consultative Council with around 80 experts.

The Steering Committee adopted the final draft on 6 May 2021 and the Principles on Effective Interviewing for Investigations and Information Gathering were officially launched on 9 June 2021.