A Comparative Forensic Analysis
This work constitutes the first approach to studying forensic odorology in Cuba, a technique used for criminal identification for several decades. Although certain technical elements and the degree of institutionalization of this practice in the country are recognized, the purpose of this publication is not to validate its effectiveness but to raise a critical discussion about the risks involved in its application when used as only incriminating evidence, especially in contexts where essential due process guarantees have been violated. In particular, its use without the support of complementary evidence is questioned in proceedings that compromise fundamental rights such as the presumption of innocence, the right to challenge evidence, and access to an effective defense.
The so-called “scent fingerprint” —also known as odorprintor “olfactory signature”—refers to the idea that each person has a unique body odor, potentially usable as an identification method, just like fingerprints or DNA. This notion is based on the premise that the chemical composition of human odor is specific to each individual. However, the reliability of this technique remains a matter of scientific debate, as factors such as environment, health, diet, or the passage of time can affect the consistency of the odor. Furthermore, the lack of standardized terminology —ranging from odorprint, odor signature, and osmology in odorology— confuses the scientific and legal fields.
The use of olfactory evidence in criminal investigations has a lengthy historical background, from using sniffer dogs centuries ago to the emergence of forensic odorology as a discipline in the Soviet Union in the 1960s. Its development in East Germany later spread to other countries in the socialist bloc, including Cuba. While technological methods such as electronic noses are being developed, trained dogs remain the primary resource. This evolution reflects the search for more objective procedures, but a strong subjective and biological component remains in their application.
Examining the Cuban case is relevant not because of its exemplary nature but because of the tensions posed by its use in a legal context with few control and transparency mechanisms. While institutionalized investigations and procedures have been documented, their application has included cases in which the odor fingerprint has been the only evidence used to support convictions, which raises serious doubts about its evidentiary validity in the absence of procedural guarantees. This analysis does not intend to exhaust the topic but rather to offer a preliminary look that invites us to critically question the use of this technique in the Cuban penal system.
The human scent is compounded by hundreds of volatile organic compounds (VOCs) produced by metabolic processes in cells and by the action of microbes on skin secretions. Various factors influence individual odor, including genetics, diet, environment, and activities. Research has been conducted to identify “primary odors” less susceptible to external factors. Studies using gas chromatography/mass spectrometry (GC/MS) analyze and compare VOC profiles for individual identification. While there is a general understanding of the chemical components, identifying a stable and unique “primary odor” for reliable identification remains a scientific challenge due to the complexity and variability of human VOCs.
Canines possess approximately 2 billion olfactory cells, significantly more than humans, giving them superior scent detection capabilities. Dogs can detect an odor source with a single odorant molecule. Canines are used in various forensic applications, including detecting drugs, explosives, human remains, and scents. The canine nose remains the gold standard for scent detection due to its sensitivity and ability to work with complex odor mixtures. Current technology has not yet fully replicated the efficiency of the canine olfactory system.
Canine odor detection relies on olfactory cells with cilia that capture odorant molecules. Canine olfactory memory allows them to recognize and differentiate odors. Training methods that leverage operant conditioning associate specific odors with rewards. Understanding canine odor detection’s biological and neurological mechanisms is crucial for optimizing training and interpreting results. This knowledge helps develop effective training protocols and understand the limitations and capabilities of canine odor work.
An analysis of information available in official Cuban media, including provincial sources, reveals mentions of the use of the so-called “scent fingerprint” in police work. Articles published in Cubadebate allude to its use by trained dogs and describe practices such as preserving traces on objects (for example, rags inside doorknobs). However, contradictory statements are also recorded: in one case involving cattle rustling, a manager stated that a scent print alone was not enough to incriminate someone, which suggests some recognition, at least discursive, of its evidentiary limitations. This ambivalence in the public treatment of the subject shows that, although the technique has institutional acceptance, there is no consensus on its legal scope nor a clear definition of its value as an autonomous means of proof.
Regarding technical development, Cuba established an odorology laboratory in 1989 based on the Soviet model and has developed its procedures for collecting and comparing scent traces. It is claimed that hygiene and sterility protocols similar to those used in microbiology are followed and that analyses are performed in climate-controlled chambers with trained dogs for at least 16 weeks. This institutional and methodological framework denotes a degree of formal structuring. However, the existence of protocols does not guarantee the reliability of evidence, especially if external control mechanisms, adequate judicial supervision, or the possibility of technical contradiction by the defense does not accompany them.
According to local technical sources, Cuban criminalists maintain that human scent is consistent across different body parts and can persist after death, which would, in theory, allow a person to be identified even if the trace comes from a different body segment than the one from which the suspect’s sample was taken. While these findings support the operational viability of the technique, its International scientific acceptance is still limited and not without controversy. Therefore, its use in criminal proceedings—especially as sole evidence—raises serious questions about respect for due process and the validity of convictions based exclusively on this opinion.
A review of academic studies and publications in Cuba on the “scent signature” reveals a sustained interest and constant production in this area. Researchers such as Rafael Hernández de la Torre of the University of Havana have published on forensic odorology since the early 2000s. The Cuban Magazine of the Supreme People’s Tribunal boarded in 2004 the judicial assessment of the odorological expert opinion. Various academic theses – such as those of Marcos Molina Waldemiroff (2008) and Ormany Carbonell Vidal (2011)—have explored this technique’s methodological, chemical, and legal aspects. This academic activity demonstrates an Institutional effort to formalize and scientifically support odorology in Cuba. However, it should not be understood as fully validating its evidentiary reliability in legal contexts.
When analyzing these investigations, Cuban’s methodology involves collecting scent traces from objects or surfaces touched by the alleged perpetrator and then comparing them using trained dogs in controlled environments. It insists on maintaining hygienic and sterile conditions to avoid contamination. However, these statements come almost exclusively from endogenous sources. They are not contrasted with international reviews or independent scientific or judicial validation mechanisms.
In the literature reviewed, considerable confidence in the uniqueness of human scent and its postmortem persistence are elements presented as scientific foundations of the technique. However, this institutional security contrasts with international criticism that questions the reproducibility of the results and the risk of errors when using this technique as the only incriminating evidence. The lack of internal debate or independent reviews of the limits of odorology in Cuba suggests a predominantly one-dimensional view of the problem.
Detailed exploration of how “scent fingerprinting” techniques are used in other countries reveals a widespread practice. Argentina uses dogs with olfactory memory to detect crimes that occurred years ago. Denmark, the Netherlands, Belgium, Sweden, Germany, and Hungary use odorology to varying degrees. The Dutch police have a Danish program for olfactory memory dogs. Olfactory identification parades are used in several countries, including the United States and Europe. Mexico is considering implementing forensic odorology units. Forensic odorology is not unique to Cuba and is practiced in several countries, indicating broader international interest in this technique. The diverse list of countries suggests that, while methodologies may differ, the underlying principle of using odor for identification is internationally recognized.
The international comparison of different methodologies for collecting, preserving, and analyzing olfactory evidence highlights canine and instrumental methods (electronic noses, GC/MS). Electronic noses seek to mimic the human nose by using sensors to detect VOCs and create an odor print. GC/MS is used to analyze the chemical composition of human odors and identify individual VOC profiles. Canine olfactory lineups involve presenting the dog with an odor from a crime scene and comparing it with suspect odors. The international landscape shows a trend toward integrating technological advances with traditional canine methods for a more comprehensive approach to odor analysis. This integration aims to leverage the strengths of both biological and instrumental detection to improve accuracy and reliability.
The review of international academic research on the effectiveness and reliability of forensic odorology reveals a recognition of its potential but also highlights ongoing debates and the need for further standardization and validation. Research focuses on the uniqueness and persistence of human scent. Studies investigate the accuracy of canine scent lineups. The technique remains controversial despite its usefulness, with debates surrounding the algorithm for dog identification of human scent. Efforts are underway to optimize and standardize instruments and canine training to improve reliability. International academic research recognizes the potential of olfactory evidence but also highlights ongoing debates and the need for further standardization and validation. The controversy arises from the subjective nature of canine identification and the challenges of fully understanding the complex science of human scent.
A direct comparison of the methodologies, training standards, and legal frameworks applicable to olfactory evidence in Cuba and other countries reveals that the Cuban approach is intensely focused on canine odorology, with a consolidated institutional trajectory since the late 1980s. However, internationally, there is a trend toward methodological diversification, with a growing emphasis on instrumental techniques—such as electronic noses or chemical analysis—and the creation of objective validation standards. Organisms like the American Academy of Forensic Sciences Standards Board(AAFS-SB) and the Global Forensic and Justice Center(GFJC) have promoted more rigorous regulatory frameworks, including certification processes, continuous assessment, and evidentiary admissibility criteria. The lack of explicit references to adherence by the Cuban system to international standards raises doubts about the comparability and reliability of its procedures.
Although Cuba’s accumulated experience and the existence of internal protocols could be considered relative strengths, these should be examined with caution. Lack of external validation, independent auditing, or integration of complementary scientific methods constitutes a significant limitation. The almost exclusive reliance on the canine component, without systematic contrast with instrumental methods, can compromise the objectivity of the analysis. Furthermore, the lack of transparency in the management of this evidence, and the opacity in the judicial admission of odorological opinions, reinforce the need for a critical review of the Cuban model.
Finally, it cannot be ignored that Cuba’s political and judicial system – characterized by structural limitations on judicial independence, access to effective technical defense, and the lack of robust mechanisms for contradicting evidence –Strongly influences how forensic odorology is used and assessed in criminal proceedings. Academic and technological isolation, along with restrictions on access to specialized literature and limited participation in international forensic science networks, limits the potential for technical evolution of the Cuban approach and amplifies the risks of due process violations when this technique is used as central or exclusive evidence.
In the Cuban context, the olfactory evidence—mainly in the form of expert opinions supported by canine identification parades—has been regularly used in criminal investigations. Although there is no explicit case law regulating its evidentiary value, its use has been reported in official media as Cubadebate, where its use by the police in cases of cattle rustling is mentioned. However, even in these spaces, some voices recognize that a “scent trace” on its own should not be enough to justify a conviction, which suggests some practical awareness of its limits as a stand-alone test. Despite this, the absence of clear procedural regulations on their admission, contradiction, and judicial assessment poses significant risks to respect for due process guarantees.
Cuban practice contrasts with trends observed in international legal systems, where the admissibility of olfactory evidence has been the subject of intense scrutiny. In the United States, for example, court decisions such as United States v. Wade(2007) have raised doubts about the reliability of this technique, while other failures such as People v. Benigno Salcido(2005), have admitted its use, but subject to compliance with strict scientific standards, including validated protocols, certified training, and performance testing for canine pairs. These criteria address recurring concerns regarding the validity of olfactory recognition wheels, the lack of replicable mechanisms, and the lack of understanding of the exact neurocognitive processes involved in canine identification.
In this sense, the lack of transparency about the methods used in Cuba—such as the criteria for selecting, training, and validating dogs or judicial control over the chain of custody of traces—Creates uncertainty about the reliability of expert opinions presented to the courts. At the international level, organisms like the American Academy of Forensic Sciences Standards Board(AAFS-SB) and the Global Forensic and Justice Center(GFJC) have promoted standards for the certification of canine teams and the standardization of collection, preservation, and analysis protocols. Equivalent frameworks or independent scientific or judicial audit mechanisms have not been documented in Cuba.
The chain of custody is essential for the admissibility of any forensic evidence. Its vulnerability in the case of odor traces – due to its volatile and easily contaminated nature – requires exceptional precautions. The lack of external controls, the lack of participation of independent experts, and the impossibility of verification by the defense aggravate the situation in the Cuban context. In short, although forensic odorology has been institutionalized in Cuba, its use as the sole incriminating evidence without robust procedural guarantees represents a direct threat to the principle of the presumption of innocence and the right to an effective defense.
This work constitutes the first approach to analyzing the application of forensic odorology in Cuba, emphasizing the “scent fingerprint” technique as a means of criminal identification. While a significant degree of institutionalization is noted—with a specialized laboratory since 1989 and its protocols for collection and canine training—The critical review reveals a series of structural weaknesses that warrant an urgent debate on their use in the Cuban criminal justice system.
Olfactory evidence in Cuba relies almost exclusively on canine identification parades. However, there are no public, independent, and verifiable protocols for the scientific validation of this methodology. Furthermore, the technique has sometimes been used as primary or even sole evidence in criminal proceedings, constituting a significant risk to the rights of defense and respect for due process.
Compared to the international context, Cuban practice shows a worrying disconnect with the certification and validation standards promoted in other jurisdictions. Odor evidence is admitted on a subsidiary basis and under strict reliability conditions. Added to this is the lack of institutional transparency and limited judicial oversight over collecting, preserving, and using odor traces.
Recommendations:
Only through a critical review, accompanied by institutional and methodological reforms, can we ensure that forensic odorology in Cuba is used within the framework of a justice system compatible with human rights and international standards of scientific evidence.