The effect of aging on crime scene objects on the results of scent identification line-ups using trained dogs

Olfato e crime: implicações do reconhecimento de odores corporais na Psicologia Forense.

Thesis

Full-text available

Mar 2016

Laura Alho

RESUMO: A resolução de crimes culmina muitas vezes com a identificação de um ofensor por parte da vítima. No entanto, tem sido verificado que as testemunhas oculares e auriculares são altamente falíveis, o que se tem revelado um tema de preocupação e de discussão entre investigadores forenses e entidades policiais. Uma vez que as investigações têm incidido maioritariamente nos sentidos da visão e da audição, propusemos uma nova linha de investigação que pretende estudar a possibilidade de o olfato também poder ser considerado na resolução de crimes. Em determinadas condições, as observações feitas pelas vítimas acerca do odor do ofensor podem desempenhar um papel determinante na fase investigativa do processo. A presente tese propõe como linha de investigação o “testemunho olfativo”, pretendendo perceber (i) a capacidade dos humanos na identificação de odores corporais de estranhos em alinhamento (um paradigma semelhante aos testemunhos ocular e auricular), (ii) a memória olfativa em contexto emocional e em contexto neutro, (iii) os efeitos de algumas variáveis (de sistema e estimadoras) na identificação do odor-alvo em alinhamento. Todos os estudos apresentam, de uma forma geral, a mesma metodologia: exposição a vídeos reais (de crime ou neutros) e a apresentação simultânea de um odor corporal que é informado ser do elemento do sexo masculino que se vê no vídeo. Após uma pausa de 15 minutos, é apresentado um alinhamento com odores onde o odor-alvo está ou não presente. A metodologia foi ajustada especificamente para cada estudo. O Estudo 1 explorou o paradigma do testemunho ocular num contexto emocional (crime) e num contexto neutro (n = 80), com uma tarefa de reconhecimento forçada (i.e., o odor-alvo estava sempre presente). Os resultados demonstraram que em ambas as condições, o reconhecimento foi realizado acima do acaso, tendo sido verificado um desempenho estatisticamente significativo entre a condição crime (68%), comparativamente com a condição neutra (45%) (p ≤ .05). O Estudo 2 testou os efeitos do intervalo de retenção apenas na condição emocional (crime). Foi utilizado um intervalo de retenção curto (IRC, 15 minutos) e um intervalo de retenção longo (IRL, 1 semana). Os resultados mostraram um decréscimo na identificação na condição IRL. No IRC, os participantes foram capazes de identificar o odor-alvo acima do acaso (p ≤ .05). Ao fim de uma semana, a taxa de acerto não se diferenciou da probabilidade do acaso (p > .05). O Estudo 3 explorou os efeitos do tamanho do alinhamento na condição emocional. Foram apresentados alinhamentos de 3, 5 e 8 odores corporais. Os resultados revelaram que nas três condições o reconhecimento foi feito acima do acaso (p ≤ .05). No entanto, à medida que o alinhamento aumenta, a proporção de respostas corretas diminui, sugerindo que em alinhamentos pequenos o reconhecimento é mais eficaz. O Estudo 4 explorou o tipo de aprendizagem (acidental vs. intencional) na condição emocional (crime), com instruções diferenciadas para ambas. Os resultados mostraram a inexistência de diferenças significativas entre as condições, propondo que o reconhecimento olfativo não sofre interferências com as instruções e com o tipo de aprendizagem relativa ao odor-alvo no momento da codificação. O reconhecimento em ambas foi significativamente acima do acaso (p ≤ .05). O Estudo 5 manipulou a presença e a ausência do odor-alvo em alinhamentos de 5 odores corporais, na condição crime e na condição neutra. Os resultados revelaram que a memória olfativa parece funcionar melhor em alinhamentos onde o odor-alvo está presente. Uma vez mais, o reconhecimento em ambas as condições foi acima do acaso (p ≤ .05), verificando-se um desempenho superior na condição crime, o que corrobora e replica os resultados do Estudo 1. Finalmente, o Estudo 6 explorou o tipo de alinhamento (simultâneo vs. sequencial), manipulando a presença e a ausência do odor-alvo, em ambas as condições (crime e neutra). Foi possível identificar o odor-alvo, acima do acaso (p ≤ .05) nos dois tipos de alinhamento e o desempenho foi superior nos alinhamentos que têm o odor-alvo presente. Foram realizadas análises agregadas de todos os estudos desenvolvidos de forma a perceber o efeito de variáveis como o sexo dos participantes, a posição serial do odor-alvo em alinhamento, o efeito das emoções negativas (stresse e ansiedade), e o efeito da confiança reportada na identificação olfativa. Os resultados não revelaram diferenças entre sexos no reconhecimento de odores para nenhuma condição. No que diz respeito à posição serial, assiste-se a um efeito de primazia nos alinhamentos simultâneos, mas não se assiste a nenhum efeito nos alinhamentos sequenciais, provavelmente devido ao tipo de instruções e ao tipo de julgamento diferenciado inerentes a cada tipo de alinhamento. Relativamente aos níveis subjetivos de stresse e de ansiedade, os participantes da condição emocional reportaram níveis mais elevados em todas as medidas aplicadas antes e depois da tarefa, comparativamente com os participantes da condição neutra. No entanto, apesar das diferenças, a média dos níveis reportados é baixa, pelo que não se pode inferir que os participantes experienciaram emoções negativas fortes que pudessem afetar o reconhecimento. Finalmente, os níveis de confiança dos participantes da condição crime foram superiores aos da condição neutra. No entanto, não existe uma correlação significativa entre os níveis de confiança e a precisão das respostas. Pela primeira vez na literatura científica, mostrou-se que o reconhecimento de indivíduos através do odor corporal é possível (e significativamente acima do acaso) em alinhamentos com cinco odores corporais, onde o odor-alvo está presente. O ser humano é capaz de fazer a identificação quer numa condição emocional, quer numa condição neutra. No entanto, o reconhecimento na condição emocional parece ser potenciado, sugerindo que a emoção negativa associada a esse evento pode intensificar a recordação do odor em tarefas posteriores de reconhecimento. No entanto, apesar destes resultados interessantes e promissores, importa realçar que é necessária cautela na transposição para o contexto real. Para que o testemunho olfativo seja aplicado no terreno, ainda há um longo percurso pela frente. Ainda assim, este projeto de investigação demonstrou que o olfato pode ser uma ferramenta útil e efetiva em contextos forenses e que merece ser explorado em investigações futuras. ABSTRACT: The majority of criminal investigations frequently culminates in the identification of an offender by the victim. However, it has been shown that eye- and earwitnesses are highly fallible, which is proving a topic of concern and discussion among forensic investigators and law enforcement agencies. Since the research has mainly focused on the senses of sight and hearing, herein we proposed a new line of research that aims to study the possibility of olfaction to be considered in criminal investigations. Under certain conditions, the observations made by victims about the offender's body odor can play a decisive role in the investigative procedure. This thesis presents as a new research line the "nosewitness identification," intending to investigate (i) the ability of humans to identify body odors of strangers in lineups (a paradigm similar to that used in eye- and earwitnesses), (ii) the olfactory memory in neutral and emotional contexts (crime), (iii) the effects of some system and estimator variables in the identification of the culprit odor in lineups. Generally, all the presented studies had the same methodology: exposure to real videos (crime or neutral) and the simultaneous presentation of a body odor that was informed to be from the male seen in the video. After 15 minutes, a lineup with odors was presented in which the culprit odor was present or not. The methodology was adjusted specifically for each study. Study 1 explored the paradigm of eyewitness testimony in an emotional (crime) and a neutral context (n = 80), in a forced-choice recognition task (i.e., the culprit odor was always present). The results showed that in both conditions, the identification was performed above chance level, showing a statistically diference in the crime condition performance (68%) compared to the neutral one (45%) (p ≤ .05). Study 2 tested the effects of retention interval only in the emotional condition (crime). A short retention interval (SRI, 15 minutes) and a long retention interval (LRI, 1 week) were used. The results showed a decrease in the identification in the LRI condition. In the SRI, participants were able to identify the culprit odor well above chance (p ≤ .05). However, after one week, the correct identification rate was not different from the probability of chance level (p > .05). Study 3 explored the effects of the lineup size on the emotional condition. Lineups with 3, 5 and 8 body odors were presented. The results showed that the correct identifications were above chance in all conditions (p ≤ .05). However, as the lineup increased, the proportion of correct identification decreased, suggesting that in small lineups, recognition is more effective. Study 4 explored the type of learning (intentional vs. incidental) on the emotional condition (crime), with different instructions for each one. The results showed no significant differences between conditions, suggesting that the olfactory identification did not impaired in function of the instructions and the type of learning at the encoding of the culprit odor. The correct identifications in both conditions were significantly above chance (p ≤ .05). Study 5 manipulated the presence and the absence of the culprit odor in lineups with 5 body odors, in the neutral and emotional conditions. The results showed that the olfactory memory seems to work better with lineups where the culprit odor was present. Once again, the correct identifications in both conditions were significantly above chance level (p ≤ .05), with a higher performance at the crime condition, which supports and replicates the results of the Study 1. Finally, Study 6 explored the type of lineup (simultaneous vs. sequential), manipulating the presence and absence of the culprit odor in both conditions (crime and neutral). It was possible to identify the culprit odor well above chance (p ≤ .05) in both types of lineup. Moreover, the performance rate was higher in lineups where the culprit odor was present. Aggregated analyzes were performed for all studies in order to understand the effect of variables such as the participants’ sex, the serial position of the culprit odor in the lineup, the effects of negative emotions (stress and anxiety) and the confidence reported on nosewitness identification. The results revealed no differences between sexes in the identification of any condition. With respect to the serial position, the results showed a recency effect in the simultaneous lineups, but in the sequential lineups the results showed no significant effects, probably due to the type of instruction and to the different kind of judgment related to each lineup type. With regard to subjective levels of stress and anxiety, participants in the emotional condition reported higher levels in all measures assessed before and after the task, compared to participants in the neutral condition. However, despite the differences, the average levels were low, so it can not be inferred that participants experienced strong negative emotions that might have affected the identification. Finally, the levels of confidence of the participants of the crime condition were higher than in the neutral condition. However, there was a non significant correlation between the confidence levels and the correct identifications. For the first time in the scientific literature it was demonstrated that identification of individuals through body odors is possible (and significantly above chance) in lineups with five body odors, where the culprit odor is present. The human being is capable of identifying either in an emotional condition or in a neutral one. However, the identification in the emotional condition appears to be enhanced, suggesting that the negative emotion associated with this event can strengthen the memory of the odor in later recognition tasks. Nevertheless, despite these interesting and promising results, some caution in conveying these results to the real context is required. For the nosewitness model to be implemented in the field, there is still a long way ahead. Still, this research project has shown that smell can be an useful and effective tool in forensic contexts and which deserves to be further explored.

POLICE PROGRAMS, CANINES, AND CONTINGENCY THEORY: AN EXPLANATION OF CANINE NUMBERS AMONG LARGE POLICE DEPARTMENTS

Article

David Wayne Welker

Biological organisms as volatile compound detectors: A review

Article

Oct 2013

The detection and identification of volatile compounds is essential to the successful undertaking of numerous forensic analyses. Biological olfactory systems possess the extraordinary ability to not only detect many thousands of distinct volatile compounds (odors) but also to discriminate between them. Whole-organism biological sensors, such as detection canines, have been employed in forensic science as volatile compound detectors for many years. A variety of insects including bees, wasps, and moths, which have also been shown to detect volatile compounds of forensic significance, have been investigated for their potential application in field-based detection systems. While the fundamental aim for many developers of portable instruments is to replicate the remarkable ability of biological olfactory systems, such analytical equipment is yet to possess the detection and discriminatory powers achieved by biological sensors. Recent literature reveals an increasing interest in olfactory receptors - the biological components that impart olfactory ability - for detecting volatile compounds associated with forensically significant substances such as explosives and illicit drugs. This paper reviews the literature regarding the current, and potential future, use of biological organisms as sensors for forensic science applications.

Influence of biotic and abiotic factors on the performance of service dogs of different genotypes

Article

Sep 2024

Aim. In the current situation of Russia's military invasion of Ukraine, national security, territorial integrity and state sovereignty are extremely important for the country's dog services. The benefits of using dogs are much greater than the costs of their maintenance and training. Dogs search for explosive devices, missing soldiers and their remains, detain criminals, and guard military facilities. Different breeds of service dogs are preferred for each special task. Purpose: to study the methods of training service dogs of different breeds of detection service by scent trail and to analyse certain factors affecting the quality of the dog's work. Methods. The research on the topic of the scientific work was conducted in the conditions of the dog training center of the Ministry of Internal Affairs of Ukraine in Vinnytsia region. The following methods were used in the research process: zootechnical, analytical, calculation, biometric. The research materials were used for the study of German Shepherd, Labrador Retriever and Rottweiler dogs, which underwent a general training course and special training for detective work on human scent trails. Results. Service dogs have been used in human life for centuries to protect important facilities and territories, mine clearance, customs service, detention of criminals, search and rescue of people. Training of different breeds of dogs for a particular type of activity, painstaking and careful work of dog handlers, on which the results of dog performance in different conditions of their use depend. Conclusions. The testing of sniffer dogs for human scent detection was carried out in accordance with the existing rules and methods used in the dog training centers of the National Police of Ukraine. The conditions of keeping and feeding the dogs met the standards and recommendations, taking into account the breed, age, live weight, specifics of work and workload, which allowed us to obtain reliable results in the experiments. In the organisation of training and coaching of service dogs, all our studied factors will help dog handlers to use the dog methodically and competently in real circumstances.

Do Reconhecimento de Pessoas e Objetos – A Identificação pelo cheiro: Ciência e Prática Policial

Article

Full-text available

Jul 2022

Linhares dos Reis

No âmbito do processo penal português, a identificação de suspeitos e arguidos através dos designados reconhecimentos atípicos (olfativo), é uma diligência de investigação criminal, que pela sua especificidade, fragilidade e falibilidade, deve ser sustentada pela ciência e apoiada em procedimentos policiais robustos que garantam a inviolabilidade da custódia da prova processual penal, uma vez que do seu resultado, em crimes de excecional complexidade (e.g., terrorismo, violação, rapto), poderá depender uma acusação ou absolvição em Tribunal. Também no reconhecimento de objetos, porque, no geral, associados diretamente ao crime, devem ser implementados idênticos procedimentos aos usados para identificar as pessoas nos termos da lei processual penal. Para que o desempenho da testemunha seja preciso e confiável à luz da autoridade judicial que decide, é essencial que as polícias implementem estes atos processuais, segundo protocolos compostos por procedimentos técnicos baseados na ciência. Perceber a complexidade da temática que envolve o olfato (odores corporais e outros), as variáveis que influenciam a memória e perceção da testemunha e, por este meio, contribuir para uma maior consciencialização da problemática, foi o propósito desta resenha bibliográfica.

PES VERSUS GC/MS: CITLIVOST VŮČI LIDSKÉ PACHOVÉ SIGNATUŘE

Conference Paper

Full-text available

Jan 2018

V současné době se identifikace lidského pachu provádí za pomoci speciálně cvičených psů. Tato metoda se nicméně řadí mezi subjektivní metody a jako taková má signifikantně nižší důkazní hodnotu než otisky prstů či DNA. Předpokládá se, že vhodná analytická technika by byla značně více respektována ve forenzních i soudních kruzích než subjektivní metoda prováděná za použití speciálně vyškolených psů. Nicméně vývoj takovéto metody je teprve v počátečních stádiích. Existuje ovšem základní otázka: Je současná analytická technika dostatečně citlivá pro spolehlivou identifikaci lidského pachu? Cílem této studie bylo porovnání citlivosti čichového ústrojí speciálně cvičených psů s citlivostí plynové chromatografie s hmotnostní detekcí (GC/MS) s ohledem na molekuly tvořící pachovou signaturu. Naše experimenty ukázaly, že speciálně cvičení psi mají výrazně vyšší citlivost na pach než standardní GC/MS. Citace: P. Cinková, P. Doležal, J. Lněničková, L. Pinc, Š. Urban; Pes versus GC/MS: Citlivost vůči lidské pachové signatuře; Sborník příspěvků z mezinárodní vědecké kriminalistické konference "Pokroky v kriminalistice 2017" konané na Policejní akademii České republiky v Praze v dnech 12. a 13. září 2017, Praha 2018, str. 35–42, ISBN: 978-80-7251-485-4. Pozn. Cinková je rodné příjmení autorky P. Pojmanová

Influences of breath sample re-use on the accuracy of lung cancer detection dogs

Article

Full-text available

Oct 2022

Evaluations of dogs as lung cancer detectors using breath samples have produced a variety of results, some quite promising. Breath samples are typically collected onto a substrate and stored in a sealed container when not in use, but volatile compounds dissipate when the substrate is exposed during training and evaluation sessions. Collection of appropriate samples for training and testing dogs requires significant resources and strict control of recruitment and sample collection processes. Therefore, some researchers re-use samples while training dogs. No systematic evaluation of the effect of sample re-use on dogs’ training performance has been conducted, so the influence of this potentially important training factor is not known. We trained seven dogs to indicate the presence of lung cancer positive breath samples using an automated apparatus. The samples were stored at -60°C or -80°C. Samples from 460 individuals who were classified as positive or negative for lung cancer were used for training samples. Individual samples were presented to dogs up to four times over a period of two years. As sample re-use increased, sensitivity declined (-6.65, p = <.001, 95% CI [-10.56, -2.76]), specificity increased (2.87, p = .036, 95% CI [.19, 5.55]), and the dogs’ bias shifted in the direction of a negative indication bias (-.094, p = <.001, 95% CI [-.149, -.39]). However, there were no significant changes in the measure associated with the detectability of the target (-0.30, p = .285, 95% CI [-.087, .26]). All observed changes in performance across sample re-use were small. Therefore, these findings suggest that sample re-use may be appropriate for training, but additional research is required to determine which factors underly changes in performance as breath samples are re-used.

Individual human scent as a forensic identifier using mantrailing

Article

Nov 2017
FORENSIC SCI INT

Specially trained dogs have long been used by law enforcement agencies to help in criminal investigations and in searching for missing persons. Still, it is unclear which components of human scent released into the environment contribute to successful searches of individuals. In this study, saliva and axillary sweat samples were taken from a total of 190 people. Additionally, DNA was extracted from whole blood of seven different people and used as an odour sample as well. Overall 675 tests (trails) were performed during a period of 18 months. The ability to track individuals with the odour samples mentioned above was examined with seven dogs, four of which were specially-trained dogs (mantrailer) from the Saxony Police. Results indicated that specially-trained police dogs can track a person with an average success rate of 82% and correctly identify the absence of an odour track with an average success rate of 97% under various conditions. Private rescue dogs were less successful with an average success rate of 65% and 75% respectively. These data suggest that the potential error rate of a well-trained handler team is low and can be a useful tool for law enforcement personnel. Saliva, as a reference odour source, was found to be particularly suitable for the search. The results of the study suggest that the components contained in axillary sweat, saliva and DNA extracted from whole blood are sufficient, serving as a key stimulus for individualized searches.

Reconhecimento de odores corporais em situações de crime. (Body odor recognition in crime situations).

Thesis

Full-text available

Dec 2011

Laura Alho

RESUMO (PT): Uma das formas mais antigas de os organismos se relacionarem entre si e com o meio envolvente é através da estimulação química olfativa, que desempenha um papel determinante em comportamentos de sobrevivência. Os odores corporais modelam a nossa interação com os outros, funcionando como um alerta para potenciais ameaças e despoletando respostas de luta/fuga. Devido à sua relevância ecológica, este tipo de odores é processado de modo singular, relativamente aos odores comuns, constituindo uma área de investigação recente. A inexistência de estudos que explorem as aplicações dos odores corporais em situações de crime, utilizando alinhamentos em que o reconhecimento seja feito por humanos, levou-nos a conduzir esta investigação. Aliado ao facto de que somos bons na deteção e discriminação de odores e que cada indivíduo possui um odor corporal único que pode ser transferido entre pessoas e objetos, colocámos como principal questão de investigação se serão essas capacidades potenciadas em circunstâncias que envolvam maior vulnerabilidade física e emocional (e.g., crimes). Foram apresentados filmes de crime (grupo experimental) e filmes de controlo (grupo de controlo) ao mesmo tempo que os participantes cheiravam um odor corporal, que instruímos ser do perpetrador no caso dos filmes de crime, ou do homem presente no caso dos filmes de controlo. Os participantes teriam de, por aprendizagem acidental, reconhecer em alinhamento o odor a que estiveram expostos durante o filme. Os principais resultados mostraram que o grupo experimental teve maior número de acertos (68%) comparativamente com o grupo de controlo (45%), sendo esta diferença estatisticamente significativa. Os resultados apontam assim para as potenciais implicações dos odores corporais no âmbito forense ao nível da redução da probabilidade de erro no reconhecimento de pessoas inocentes e na formação de órgãos de polícia criminal que podem desenvolver estratégias para as suas investigações. A compreensão do olfato em situações onde a sobrevivência é colocada em risco pode ser crucial na intervenção com vítimas e/ou testemunhas de crime. ABSTRACT: One of the oldest forms of how organisms relate to each other and the environment is through the olfactory chemical stimulation, which plays a key role in survival-related behaviors. Body odors shape our interaction with others, working as an alert to potential threats and therefore triggering fight and/or flight responses. Due to its ecological relevance, such odors are processed in a unique way, different from common odors, and their study represents a recent area of research. The lack of studies exploring the applications of body odors in crime situations using line-ups in which the recognition is done by humans, led us to conduct this research. Coupled with the fact that we are good at detection and discrimination of odors and that each individual has a unique body odor that can be transferred between people and objects, our main question is whether these capabilities will increase in circumstances that involve physical and emotional vulnerability (e.g., crimes). Participants viewed crime films (experimental group) and control films (control group) which were presented while they smelled a body odor that we instructed to be from the perpetrator in the case of the crime scenes (and from the male presented in the control scenes). The participants’ task was to recognize the target-odor in a line-up of body odors by incidental learning. The main results showed that the experimental group had a higher number of correct answers (68%) compared to the control group (45%), with this difference being statistically significant. Thus, the results point to the potential implications of body odors in forensics in reducing the probability of error in the recognition of innocent people and in the training of criminal police forces who can develop strategies for their investigations. The understanding of smell in situations where survival is at risk can be crucial in the intervention with victims and / or witnesses of crimes.

Olfato e crime: Os odores corporais como ferramenta da investigação criminal e da psicologia forense

Article

Full-text available

Jan 2014

A prova testemunhal – mais especificamente a prova por reconhecimento – está enquadrada no Código do Processo Penal portu- guês e é amplamente usada em tribunal. Todavia, várias investigações têm apontado falhas na validade dos testemunhos que le- vam à condenação de pessoas inocentes. Considerando que a memória e a perceção podem sofrer interferências e enviesamentos que levam, em última análise, ao reconhecimento incorreto de suspeitos, a literatura científica tem-se debruçado no estudo de va- riáveis e de novos paradigmas que possam diminuir as falsas identificações. O reconhecimento de ofensores através das testemu- nhas oculares e auriculares tem sido alvo de estudo ao longo de várias décadas. De igual forma, o reconhecimento através de odo- res corporais tem sido investigado, sendo realizado por cães treinados por unidades policiais especializadas. Esta identificação de suspeitos, baseada nos odores corporais, faz parte da peritagem forense em vários países europeus e é introduzida como prova em tribunal. Recentemente foi levantada a hipótese de os humanos também serem capazes de reconhecer ofensores através dos odo- res corporais. Este artigo pretende fazer uma revisão sobre os vários tipos de testemunho, apontando para a instrumentalidade dos odores corporais na investigação criminal e na psicologia forense, quer enquanto evidência física, quer como pista que pode ser crucial no decurso da própria investigação.

Testemunho olfativo: potencialidades dos odores corporais na investigação criminal

Article

Full-text available

Jun 2013

Human Scent Detection: A Review of its Developments and Forensic Applications

Article

Full-text available

Jan 2008

Sarcoptic-mange detector dogs used to identify infected animals during outbreaks in wildlife

Article

Full-text available

Jul 2012
BMC Vet Res

One of the main aims of forensic investigation is the detection and location of people and substances of interest, such as missing people and illegal drugs. Dogs (Canis lupus var. familiaris) have had an important role in legal and forensic investigations for decades; nonetheless canines' keen sense of smell has never been utilized in either the surveillance or control of wildlife diseases. The rapid removal and treatment of infected carcasses and/or sick animals is a key task in the management of infectious diseases, but it is usually difficult or impractical to carry out in the wild. In this paper we report on a study running over a period of 15 years, in which - for the first time to our knowledge - two disease-detector dogs were trained to follow the scent of Sarcoptes-infected animals and to find carcasses, even under the snow, and apparently no false positives were detected in fieldwork. Sarcoptic mange-detector dogs were used to collect the carcasses of 292 mangy wild animals and to identify, separate from their herd, and capture 63 mange-infected wild animals in the Italian Alps. Properly trained disease-detector dogs are an efficient and straightforward tool for surveillance and control of sarcoptic mange in affected wild animal populations.

Effects of sample preservation techniques on dogs’ (Canis familiaris) ability to detect koi carp (Cyprinus rubrofuscus)

Article

Mar 2024
APPL ANIM BEHAV SCI

Living Organisms as Sensors for Biohybrid Monitoring Systems

Chapter

Full-text available

Aug 2023
Lect Notes Comput Sci

Many aquatic habitats have become vulnerable to rapid and long-term changes induced by industrialism, air pollution, tourism, fishing activities etc. These factors created an urgent need for extensive water monitoring and conservation. By observing the behaviour of lifeforms, we can monitor the state of the environment. Here, we present the methodology, calibration approaches and preliminary results of designing a biohybrid entity for aquatic monitoring. Biohybrid robots combine mechanical and electronic elements with living organisms or tissues. This biohybrid consists of several modules, each hosting or attracting different species and communities. We focus on animals such as Daphnia sp., zebra mussel Dreissena polymorpha and various representatives of the plankton community. The first results showed that 1) both Daphnia and D. polymorpha show no clear signs of confinement-induced stress, 2) the designed structures are examples of suitable tools for hosting the organisms, observing their behaviour and collecting and storing data and 3) their behaviour can be calibrated under laboratory conditions to be able to extrapolate the field data into environmental data.

Molekulová skladba pachové signatury

Thesis

Full-text available

Dec 2020

Petra Pojmanová

Předkládaná dizertační práce je zaměřena na studium molekulárního profilu lidského kožního pachu pomocí metod plynové chromatografie ve spojení s hmotnostní detekcí (GC-MS a GC×GC-MS). V rámci této práce je představeno několik dílčích experimentů, zabývajících se optimální přípravou pachových vzorků pro chemickou analýzu (nalezení vhodných sorpčních materiálů, vhodných rozpouštědel pro následnou extrakci pachových sloučenin, způsobu koncentrování vzorků, či testování pachů z různých částí těla). Několik experimentů se pak věnuje možnostem provedení skupinové identifikace (konkrétně diskriminaci pohlaví) ze vzorků lidského pachu, a to za použití různých způsobů provedení analýzy. Poslední popisovaný a nejrozsáhlejší experiment (504 vzorků lidského pachu od 40 dobrovolníků, v nichž bylo sledováno 67 látek) se pak zabývá nejen skupinovou identifikací, ale i identifikací individuální. Za pomoci matematické metody podpůrných vektorů byly vytvořeny modely s přesností určení pohlaví kolem 90 %, klasifikační modely pro určení jednotlivce pak dosahovaly přesnosti kolem 70 %. Dosažené výsledky ukazují, že detailní analýza molekulárního profilu pachu jedince umožňuje jak skupinovou, tak individuální identifikaci člověka, nicméně pro budoucí použitelnost ve forenzní praxi je třeba provést další experimenty, s cílem vybudovat rozsáhlou mezinárodní databázi pachových vzorků odebraných, připravených a zanalyzovaných unifikovaným způsobem tak, aby byly pachové vzorky porovnatelné a umožňovaly vytvoření přesných (více jak 95%) klasifikačních modelů.

MULTIPLICITA LIDSKÉ PACHOVÉ SIGNATURY

Conference Paper

Full-text available

Jan 2018

Vzhledem k tomu, že algoritmus pachové identifikace není dosud zcela pochopen, bylo původním cílem této práce vymezit molekuly lidské pachové signatury. Za použití preparativní plynové chromatografie byly odebrané pachové vzorky rozděleny do tří disjunktních frakcí s rozdílným chemickým složením. První frakce obsahovala vysoce těkavé organické molekuly, druhá méně a třetí velmi málo těkavé látky. Všechny frakce byly použity jako "načichávací" pachy pro srovnávací "line-up" identifikaci za použití speciálně cvičených psů. Experimenty poskytly překvapivé výsledky, protože bylo zjištěno, že psi nepoužívali jedinou frakci pachu k identifikaci. V jednotlivých srovnáních různí psi prováděli identifikace lidí na základě různých skupin molekul. Jinými slovy, vyškolení psi identifikovali jednotlivce pomocí několika pachových signatur. Tento nový experimentálně pozorovaný jev byl nazván jako multiplicita lidské pachové signatury. Tato skutečnost má závažné důsledky pro individuální pachovou identifikaci lidí i pro metody výcviku psů. Citace: P. Cinková, P. Doležal, L. Pinc, Š. Urban; Multiplicita lidské pachové signatury; Sborník příspěvků z mezinárodní vědecké kriminalistické konference "Pokroky v kriminalistice 2017" konané na Policejní akademii České republiky v Praze v dnech 12. a 13. září 2017, Praha 2018, str. 27–34, ISBN: 978-80-7251-485-4. Pozn. Příjmení Cinková je rodné příjmení autorky P. Pojmanová

La scène de crime

Book

Mar 2022

Barbara Ferry

Use of GC×GC for the characterization of odours in forensic applications

Chapter

Feb 2022
Compr Anal Chem

In forensic science, the emission of odours from objects or biological matrices is exploited for different purposes. For example, the monitoring of odours via biological or analytical detectors is used in thanatochemistry, the chemistry of death. The analysis of decomposition odour can be explored to support the localization of a missing body, a scenario encountered in urban search and rescue operations. A better understanding of the formation and evolution of decomposition odour is also of high interest to human remains detection canine handlers to improve training practices and chose appropriate training aids. Next to thanatochemistry, many other types of evidence evaluation benefit from the characterization of the volatile profile including the analysis of fire debris, chemical threat agents, explosives, and drugs. From a chemical point of view, an odour represents a complex mixture of gaseous molecules and its characterization demands for a powerful analytical technique. Especailly, in non-targeted analysis, the separation power provided by one-dimensional (1D) gas chromatography (GC) can be surpassed. Thus, a better insight is usually achieved using a multidimensional technique, such as comprehensive two-dimensional gas chromatography (GC×GC). This chapter focuses on scientific articles published between 2015 and 2020 reporting on the use of GC×GC for odour characterization in the context of forensic science. The main points are decomposition odour, volatolomic applications for profiling of human scent and illegal trade goods such as wildlife parts. Furthermore, the investigation of volatile traces of drugs and ignitable liquids in the context of arson investigations is addressed in detail. For each section, the length is proportional to the number of publications from the literature review.

Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications

Article

Full-text available

Aug 2021

Olfaction in dogs is crucial for gathering important information about the environment, recognizing individuals, making decisions, and learning. It is far more specialized and sensitive than humans’ sense of smell. Using the strength of dogs’ sense of smell, humans work with dogs for the recognition of different odors, with a precision far exceeding the analytical capabilities of most modern instruments. Due to their extremely sensitive sense of smell, dogs could be used as modern, super-sensitive mobile area scanners, detecting specific chemical signals in real time in various environments outside the laboratory, and then tracking the odor of dynamic targets to their source, also in crowded places. Recent studies show that dogs can detect not only specific scents of drugs or explosives, but also changes in emotions as well as in human cell metabolism during various illnesses, including COVID-19 infection. Here, we provide an overview of canine olfaction, discussing aspects connected with anatomy, physiology, behavioral aspects of sniffing, and factors influencing the olfactory abilities of the domestic dog (Canis familiaris).

Cadaver‐detection dogs: A review of their capabilities and the volatile organic compound profile of their associated training aids

Article

Dec 2020

Cadaver‐detection dogs (CDDs) are an essential tool for the search and detection of human remains. In order to enhance their search capability, CDDs are regularly trained on natural and synthetic training aids. The odor profile of these training aids comprises a range of volatile organic compounds (VOCs) which is intended to resemble those produced by a decomposing body. It is currently unknown if detector dogs respond to the same stimuli and whether it is a specific VOC or a suite of decomposition‐related VOCs as their target odor. This review summarizes the VOCs that have been detected in various CDD training aids such as blood, human remains, decomposition fluid, soil, buried remains, textile, and synthetic formulations. Additionally, it discusses the reported capability of CDDs to respond to each of these training aids. The purpose of this review is to understand the variability of VOCs in CDD training aids and the response of CDDs to this wide range of compounds. Additionally, this review attempts to determine if there is a specific training aid to which CDDs respond preferentially. Such a review will assist to establish better practices for CDD training since no standardized practices exist globally. This article is categorized under: • Crime Scene Investigation > Special Situations and Investigations • Forensic Anthropology > Taphonomic Changes and the Environment • Forensic Medicine > Death Scene Investigation Abstract Compounds detected by modern instruments indicating the potential volatile organic compounds detected by cadaver‐detection dogs from decomposition related material used as training aids.

A multidisciplinary approach is mandatory to solve complex crimes: A case report

Article

Full-text available

Dec 2019

Abstract Background Self-defense is legitimate both in common law and in civil law systems. Nevertheless, there remains the age-old question for the prosecutor to identify the limit between the righteous self-defense and the self-defense with excessive force. In these cases, the gathering of all evidence by a forensic multidisciplinary team is essential to provide the necessary data for the prosecutor’s evaluation. Case presentation The case of a 55-year-old man who was killed in front of his neighbor’s house is described. The prosecutor alerted the forensic team, classifying the crime as a gunshot homicide. The neighbor immediately admitted his responsibility as self-defense. Moreover, the relatives of the victim told a different version of the story, assuring that the neighbor had killed him for futile motivations. For these reasons, the prosecutor established further investigations, such as autopsy, the K-9 unit exploration, and alerting the forensic biologist for analysis. Conclusions This case aims to highlight the teamwork of multidisciplinary forensic expertise to solve complex cases; moreover, combining ultra-specialist forensic activities, such as the K-9 unit, it is possible to collect all the evidence to submit to the prosecutor for the formulation of judgment.

Multiplicity of human scent signature

Article

Full-text available

Dec 2019

Abstract Background In this paper, the term “human scent signature” refers to a group of chemical compounds in a human scent trace that are in certain relative concentrations that make an unambiguous identification of persons possible. At the present time, the scent identification of persons is performed using specially trained canines. However, the scent identification mechanism as well as the molecular composition of the human scent signature is entirely unrecognized. Delimitations of the group of chemical compounds according to their volatilities that specially trained canines use for the scent identification of persons were initially the main aim of this study. Methods Eleven volunteer scent samples were split into three groups of chemical compounds, i.e., into three disjointed scent fractions with different volatilities of the compounds via preparative gas chromatography. The human scent signatures were searched in these separated scent fractions using six specially trained canines (female German Shepherds). Results The canines were able to identify individual persons successfully using different scent fractions. From this fact, it follows that one scent trace can contain more than only one group of scent compounds that can be used for scent identification by the trained canines. This observed phenomenon was named as “the multiplicity of the human scent signature” in this study. The scent identification line-up procedure provided the following results: The poorly volatile fraction resulted in an 85% success rate in the scent identification procedure. The middle fraction resulted in a 58% success rate, and the highly volatile fraction resulted in a 30% success rate. Conclusions In this study, it was found that the human scent sample contains more than one group of scent compounds; according to which the trained canines are able to identify human individuals. It means that the human scent sample contains more than only one scent signature. The authors of this research believe that results of this study will open a broad discussion about the multiplicity of the human scent signature, primary scent molecules, optimal canine training, and in general, the scent identification method in many countries.

Testemunho olfativo: potencialidade dos odores corporais na investigação criminal (p. 226 - 244)

Chapter

Full-text available

May 2013

Laura Alho

A investigação criminal dispõe de instrumentos, tecnologias e conhecimento científico que lhe permite aumentar a probabilidade de sucesso na resolução de crimes. Na identificação de perpetradores, os testemunhos oculares e auriculares têm tido uma importância vincada, mas são altamente falíveis. Em investigação, os sentidos da visão e audição têm sido os mais pesquisados e, apesar do olfato também contribuir para o reconhecimento de perpetradores, recorrendo a cães treinados para o efeito, recentemente iniciou-se nova linha de investigação que explora o reconhecimento de odores corporais (feito por humanos) em situações de crime. O presente artigo aponta possíveis contributos dos odores corporais no contexto forense e criminal.

Decomposing Human Blood: Canine Detection Odor Signature and Volatile Organic Compounds

Article

Sep 2018

The admissibility of human “odor mortis” discrimination in courts depends on the lack of comprehension of volatile organic compounds (VOCs) during the human decay process and of the lack in standardized procedures in training cadaver dogs. Blood was collected from four young people who died from traffic accidents and analyzed using HS‐SPME/GC‐MS at different decompositional stages. Two dogs, professionally trained, were tested to exactly locate blood samples, for each time point of the experiment. We found a long list of VOCs which varied from fresh to decomposed blood samples, showing differences in specific compounds. Dog performance showed a positive predictive value between 98.96% and 100% for DOG A, and between 99.47% and 100% for DOG B. Our findings demonstrated that decomposing human blood is a good source of VOCs and a good target for canine training.

Human Remains Detection: Validity of RCMP Dog Training using Donated Human Remains through the Nova Scotia Medical Examiner Service

Article

Full-text available

Oct 2017

Preliminary development and training began in 2015 to evaluate a human remains donation procurement and dog training program in the province of Nova Scotia with a specific Royal Canadian Mounted Police handler and dog team. Human remains were donated through the procurement program at the Nova Scotia Medical Examiner Service. The human remains specimens were introduced to the human remains detection dog through scent box training and field searches. Specimens were categorized by method of concealment: above surface, under water, buried, or hanging. The team's ability to accurately detect the donated human specimens was evaluated under various weather conditions, search terrains, and varying stages of decomposition. A total of 266 training sessions were conducted during this initial development stage, of which 16 sessions resulted in false positive indications , demonstrating a training success rate of 94%.

Cani da cadavere, “dispositivo biologico specializzato” nell’individuazione di tracce ematiche latenti sulla scena del crimine. Da mito a prova scientifica

Article

Dec 2015

HuAim. The canis lupus familiaris, due to his particular olfactory characteristics, is used by the police to detect a wide range of substances (explosives, gunpowder, narcotics, etc.). Trained dogs to the discovery and reporting human remains or not visible cadaveric blood, can be of great help. This study set out to investigate and validate with scientific method, a training protocol of dogs specialized for research, tracking and reporting of cadaveric latent blood traces of blood. Methods. We used two Labrador Retriever. The study was conducted for sixteen months, with about 200 hours of simulation and 6240 surveys, within a room suitably equipped. We used blood of four patients who died due to trauma, collected in sterile and VOCs free tubes. The first phase of the training focused on the ability of the two dogs to hold the smell target and signal their presence at concentrations always decreasing. In the second phase confounding factors were introduced. Results. The study found the real effectiveness of dogs trained to identify human cadaveric blood in very low concentrations. Tests conducted have shown a good ability to discriminate human cadaveric blood in combination with confounding factors in high concentrations (olfactory accuracy). Conclusion. The use of dogs in this area necessarily requires standardization of training procedures in order to achieve “certified” for this specialized biological device the same rigorous level of reliability and reproducibility required for all methods of investigation in the forensic field, through an optimized and tightly controlled training, through the evaluation of olfactory sensitivity, the ability of olfactory discrimination and olfactory accuracy. Key words: Dogs - Cadaver - Blood - Smell.

The influence of ageing and surface type on the odour profile of blood-detection dog training aids

Article

Jul 2016

Cadaver-detection dogs are a preferred search tool utilised by law enforcement agencies for the purposes of locating victim remains due to their efficiency and minimal disturbance to the crime scene. In Australia, a specific group of these canines are blood-detection dogs, which are trained to detect and locate blood evidence and search potential crime scenes in cases where a cadaver may not be present. Their role sometimes requires searches to be carried out after considerable time has passed since the crime occurred, and this is important for developing effective training protocols. This study aimed to investigate the volatile organic compounds (VOCs) produced from fresh and aged human blood on various surfaces. Solid phase microextraction (SPME) was used to extract VOCs from the headspace of dried blood samples aged and sampled periodically over 12 months from a non-porous (i.e. aluminium) and porous (i.e. cotton) surface. Samples were analysed using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-TOFMS). Fresh blood produced distinctively different VOC patterns compared to blood aged longer than 1 week with the overall profile differing between the two surface types, and a large subset of the VOC profile found to be responsible for these differences. When analysing the various functional groups present in the samples, a common pattern between ages and surface types was observed with no specific chemical class dominating the overall profile. The results highlight the importance of evaluating training aids for scent-detection canines to ensure the greatest efficacy during training and subsequently at crime scene searches.

Review of Research Development on Environmental Odour in the Last Decade

Article

Full-text available

Aug 2012

Arief Sabdo Yuwono

The latest research development of environmental odour was reviewed in terms of the source and emission, the generated annoyance and health impact, detection and measurement systems, the most advanced abatement technologies and the role of odour in forensic science. The review was based on more than one hundred of technical papers and articles related to environmental odours that were published during the last decade. The result of the study reveals that the research development of odour in the environment in the last decade (2001-2011) has achieved a significant step in which nowadays odour is not merely concerned as an environmental pollutant, but also as an important tool for product classification as well as an instrument utilized by police to investigate criminal scenes.

Nosewitness Identification: Effects of Lineup Size and Retention Interval

Article

Full-text available

May 2016

Although canine identification of body odor (BO) has been widely used as forensic evidence, the concept of nosewitness identification by human observers was only recently put to the test. The results indicated that BOs associated with male characters in authentic crime videos could later be identified in BO lineup tests well above chance. To further evaluate nosewitness memory, we assessed the effects of lineup size (Experiment 1) and retention interval (Experiment 2), using a forced-choice memory test. The results showed that nosewitness identification works for all lineup sizes (3, 5, and 8 BOs), but that larger lineups compromise identification performance in similarity to observations from eye- and earwitness studies. Also in line with previous eye- and earwitness studies, but in disagreement with some studies on odor memory, Experiment 2 showed significant forgetting between shorter retention intervals (15 min) and longer retention intervals (1-week) using lineups of five BOs. Altogether this study shows that identification of BO in a forensic setting is possible and has limits and characteristics in line with witness identification through other sensory modalities.

Establishing the volatile profile of pig carcasses as analogues for human decomposition during the early postmortem period

Article

Full-text available

Feb 2016

Following a mass disaster, it is important that victims are rapidly located as the chances of survival decrease greatly after approximately 48 h. Urban search and rescue (USAR) teams may use a range of tools to assist their efforts but detector dogs still remain one of the most effective search tools to locate victims of mass disasters. USAR teams can choose to deploy human scent dogs (trained to locate living victims) or human remains detection (HRD) dogs (trained to locate deceased victims). However, little is known about the variation between live human scent and postmortem human remains scent and the timeframe during which one type of scent transitions to the other. The aim of the current study was to measure the change in the scent profile of human decomposition analogues during the first 72 h postmortem by measuring the volatile organic compounds (VOCs) that comprise the odour. Three pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface and allowed to decompose under natural conditions. Decomposition odour was sampled frequently up to 75 h postmortem and analysed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 105 postmortem VOCs were identified during the early postmortem period. The VOC profile during the early postmortem period was highly dynamic, changing both hourly and daily. A transition period was observed after 43 h postmortem, where the VOC profile appeared to shift from a distinct antemortem odour to a more generalised postmortem odour. These findings are important in informing USAR teams and their use of detector dogs for disaster victim recovery.

Nosewitness Testimony: Effects of Emotional Stress

Conference Paper

Oct 2015
CHEM SENSES

Nosewitness Identification: Effects of Negative Emotion

Article

Full-text available

Jan 2015
PLOS ONE

Every individual has a unique body odor (BO), similar to a fingerprint. In forensic research, identification of culprit BOs has been performed by trained dogs, but not by humans. We introduce the concept of nosewitness identification and present the first experimental results on BO memory in witness situations involving violent crimes. Two experiments indicated that BO associated with male characters in authentic videos could later be identified in BO lineup tests well above chance. Moreover, culprit BO in emotional crime videos could be identified considerably better than the BO of a male person in neutral videos. This indicates that nosewitness identification benefits from emotional encoding. Altogether, the study testifies to the virtue of body odor as a cue to identify individuals observed under negative emotion.

Cadaver dogs: Unscientific myth or reliable biological devices?

Article

Sep 2014
FORENSIC SCI INT

Dogs are commonly used to detect explosives, narcotics, and other illegal materials. In the forensic setting, cadaver dogs are trained to detect and locate concealed human remains or fluids due to the high sensitivity and selectivity of the canine olfactory system and the relative ease with which dogs can be trained and handled. The need for international and scientifically validated standards has long been outlined by the literature. It is important, therefore, to establish the reliability of the handler/dog team. Our study aimed to detect the real effectiveness of dogs trained to locate human cadaveric blood in very low concentrations, through an optimized and rigorously controlled design which would rule out any possible sources of bias. The study was designed to determine the dogs’olfactory sensitivity to human cadaveric blood and how this capacity might change as the dilution of blood increases from pure blood to very low concentrations. The further step was to examine the dogs’ability to discriminate among target (human cadaveric blood) and non–target (confounding substances) odors (discriminative capability). Our results revealed that well trained dogs were able to detect human cadaveric blood samples even when very low concentrations of blood were stored in the tubes, showing high levels of olfactory sensitivity and to discriminate the target odor even when the non–target odor was orders of magnitude higher in concentrations. Although our results are based only on two dogs, the procedure we used may provide a comprehensive answer to the need for a scientifically unassailable tool for quantifying and objectifying the performance of well-trained specific search dogs in detecting human cadaveric blood traces.

Scent‐Matching Dogs Determine Number of Unique Individuals From Scat

Article

Dec 2010
J WILDLIFE MANAGE

ABSTRACT Noninvasive scat sampling methods can generate large samples sizes, collected over vast landscapes, ideal for addressing wildlife conservation and management questions. However, the cost of genotyping scat samples limits the accessibility of these techniques. We describe detection-dog methods for matching large numbers of scat samples to the individual, reducing or eliminating the need for sample genotyping. Three dogs correctly matched 25 out of 28 samples from 6 captive maned wolves (Chrysocyon brachyurus) of known identity. Sample scent-matching can increase overall accessibility and breadth of applications of noninvasive scat-collection methods to important landscape scale problems in wildlife sciences.

Canine human scent identifications with post-blast debris collected from improvised explosive devices

Article

Jun 2010

In this study it is demonstrated that human odor collected from items recovered at a post-blast scene can be evaluated using human scent specific canine teams to locate and identify individuals who have been in contact with the improvised explosive device (IED) components and/or the delivery vehicle. The purpose of the experiments presented here was to document human scent survivability in both peroxide-based explosions as well as simulated roadside IEDs utilizing double-blind field trials. Human odor was collected from post-blast device and vehicle components. Human scent specific canine teams were then deployed at the blast scene and in locations removed from the blast scene to validate that human odor remains in sufficient quantities for reliable canine detection and identification. Human scent specific canines have shown the ability to identify individuals who have been in contact with IEDs using post-blast debris with an average success from site response of 82.2% verifying that this technology has great potential in criminal, investigative, and military applications.

Forensic and Security Applications of Substance Detection Canines

Chapter

Oct 2023

This chapter presents the use of substance detection canines from a forensic and security viewpoint. It provides the reader with a foundational framework of forensic principles that can be extended and applied to the use of canine teams as a forensic tool for odor detection purposes. It draws a special focus on key aspects of legal and security considerations to better educate the reader on optimal and efficient uses of canine teams within operational settings. Furthermore, it provides a basic introduction to the chemical aspects of odor analysis as it relates to the detection of canine performance. Lastly, it provides a synopsis of detection disciplines within substance detection canines of relevance to the forensic practice.

Toward a More Realistic 3D Biomimetic Soft Robotic Tongue to Investigate Oral Processing of Semi-solid Foods

Chapter

Aug 2023
Lect Notes Comput Sci

The current in vitro experiments reproducing food oral processing are not fully representative of the oral anatomy and of the biomechanics of the human tongue. Creating an in vitro device imitating the intricate interfacial and mechanical features, as well as the combination of motions of the human tongue, is critical to gain a quantitative understanding of how fluids and foods interact with oral surfaces. We present here a unique pneumatic three-dimensional multi-degree-of-freedom soft robotic actuator – the Biomimetic Soft Robotic Tongue (BSRT) – that embodies the mechanical performance and wettability of the human tongue, with realistic movements, and the surface roughness of the human tongue papillae. The present study presents a promising technology that can be used to realistically simulate the bolus dynamics in a variety of individual conditions, paving the way to design personalized food products meeting individual needs.KeywordsBiomimetic tonguesoft roboticsoral processingoral propulsionsemi-solid foods

Human scent characterization: A review

Article

Jun 2023
FORENSIC SCI INT

Human scent has long been cited as a probable parameter that can be exploited as a biometric measure. Identifying the scent of individual persons using specially trained canines is a well-known forensic method which is frequently used in criminal investigations. To date there has been limited research on the chemical components present in human scent and their usefulness in distinguishing between people. This review delivers insight into studies which have dealt with human scent in forensics. Sample collection methods, sample preparation, instrumental analysis, compounds identified in human scent and data analysis techniques are discussed. Methods for sample collection and preparation are presented, but to date, there is no available validated method. Instrumental methods are presented and from the overview it is clear that gas chromatography combined with mass spectrometry is the method of choice. New developments such as two-dimensional gas chromatography offer exiting possibilities to collect more information. Given the amount and complexity of data, data processing is used to extract the relevant information to discriminate people. Finally, sensors offer new opportunities for the characterization of human scent.

Other Types of Evidence

Chapter

Jan 2018

Qualitative analyses of less-volatile organic molecules from female skin scents by comprehensive two dimensional gas chromatography–time of flight mass spectrometry

Article

May 2017

Instrumental human scent analysis is undoubtedly desirable for many forensic as well medical applications. Most of the previous human scent studies were focused on volatile organic compounds (VOCs) which were analysed by head space solid phase micro-extraction gas chromatography/mass spectrometry (HS-SPME-GC/MS). This method is, however, significantly less sensitive to “heavier” less volatile compounds emitted from the human skin. These less volatile organic scent molecules probably create the basis of the individual human scent signature, and therefore, our attention is focused mainly on these “heavier” compounds. The human scent was adsorbed onto purified glass beads and samples were prepared as hexane solutions obtained by extraction from the sampled glass beads. To resolve a lot of very similar molecules, the comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometer (GCxGC-TOFMS) was used to analyse the hexane scent solutions. Using this technique, more than 137 less volatile molecules including organic fatty acids, ketones, aldehydes, simple esters, alcohols, and especially various fatty acid esters with different carbon chains were identified. A considerable number of these molecules were identified in the scent samples for the first time.

Ślady osmologiczne

Conference Paper

May 2015

Streszczenie: Osmologia jest dziedziną kryminalistyki zajmującą się identyfikacją sprawcy na podstawie pozostawionego przez niego na miejscu przestępstwa zapachu. Za pomocą odpowiednio wyszkolonych psów, zapach z miejsca zbrodni dopasowywany jest do zapachu potencjalnego podejrzanego. Praca przedstawia zarys historii osmologii w Polsce i na świecie, mający na celu usystematyzowanie wydarzeń, które doprowadziły do rozwoju tej metody. Omówione zostały także wytyczne dotyczące pobierania i zabezpieczania śladów zapachowych oraz warunków ich przechowywania. W pracy zawarto właściwości zapachu ludzkiego takie jak trwałość i intensywność, które decydują o wiarygodności tego materiału dowodowego, oraz charakterystykę zapachu na podstawie tworzących go związków chemicznych. Przedstawiono także procedurę porównywania materiału dowodowego w postaci śladów osmologicznych. Dodatkowo, w pracy ukazano również organizację szeregów selekcyjnych stosowanych w badaniach osmologicznych. Abstract: Osmology is an area of science dedicated to the identification of criminals on the basis of left odor at the scene of the crime. Using specially trained dogs allows to fit the smell from the crime scene to the smell of suspect. In this paper the history of osmology in Poland and world is described. I was also discussed guidelines for collecting and preserving such traces and storage conditions. Stability and intensity as properties of odor must be underlined. The smell is characterized on the basis of its constituent compounds. Osmological researches are performed by using specially trained dogs. The structure of the scent lineups used in osmological research is also described. Słowa kluczowe: kryminalistyka, osmologia, zapach ludzki, szereg selekcyjny, psy śledcze

Effect of age and storage conditions on the volatile organic compound profile of blood

Article

Oct 2014
Forensic Sci Med Pathol

Cadaver-detection dogs are used by the police to locate missing persons, victims of homicide, and human remains following mass disasters. Training is conducted using a variety of training aids including blood which can be hours, weeks or months old and stored under variable conditions. The aim of this study was to chemically profile human blood using solid-phase microextraction coupled with gas chromatography–mass spectrometry to determine how the volatile organic compound (VOC) profile changed over time and under variable storage conditions. The VOC profiles of fresh and degraded blood were analyzed as well as blood stored at room temperature, refrigerated, and frozen. Fresh and degraded blood samples produced distinctive VOC patterns with VOC profiles becoming more complex over time. Freezing the blood produced a complex VOC profile that was clearly discriminated from the VOC profile for blood stored at room temperature or in a refrigerator. This study highlights the importance of standardizing the age and storage conditions when using blood as a training aid to ensure cadaver-detection dogs are exposed to an accurate representation of the blood VOCs they may encounter at a scene.

Odor Biometrics

Article

Jan 2009

The success of using trained dogs to locate rodent in pest-free sanctuaries.

Article

Jan 2010

Context. Better techniques to detect small numbers of mammalian pests such as rodents are required both to complete large-scale eradications in restoration areas and to detect invaders before they become abundant or cause serious impacts on biodiversity. Aims. To evaluate the ability of certified rodent dogs (Canis familiaris) to locate Norway rats (Rattus norvegicus) and mice (Mus musculus) or their scent trails at very low densities in field conditions. Methods. We experimentally tested two rodent dogs by releasing small numbers of laboratory rats and mice in a 63ha rodent-free forest sanctuary and then determining if the dogs and their handlers could find the rodents and their scent trails. We divided the enclosure into two halves, east and west of the midpoint, and alternated releases daily between the two areas to minimise residual scent between consecutive trials. Radio-tagged rats or mice were released a total of 96 times at random locations that were unknown to handlers, followed for 50100m, then caught and either placed in hidden cages at the end of the scent trail or removed from the forest. Handlers and their dogs had up to 6h to search for rodents. Key Results. Despite the extremely low density of rodents in the effective research area of 32ha, both dogs were highly successful at finding rodents, together locating 87% of rats and 80% of mice. Handlers reported few false positive detections. We found that well-trained dogs can effectively cover 3040ha of steep forested habitat in half a day (6h). Conclusions. Despite the limitations of our study design, we conclude that well-trained rodent dogs may be able to locate wild rodents at low densities in forest situations. Implications. Our results support the ongoing use of certified dogs to detect rodent survivors and invaders in conservation areas in New Zealand and elsewhere. Additional research is required to trial dogs on experimentally released wild rodents and to compare the cost-effectiveness of dogs with other detection methods.

Cadaver dogs - A study on detection of contaminated carpet squares

Article

Jan 2008

Cadaver dogs are known as valuable forensic tools in crime scene investigations. Scientific research attempting to verify their value is largely lacking, specifically for scents associated with the early postmortem interval. The aim of our investigation was the comparative evaluation of the reliability, accuracy, and specificity of three cadaver dogs belonging to the Hamburg State Police in the detection of scents during the early postmortem interval. Carpet squares were used as an odor transporting media after they had been contaminated with the scent of two recently deceased bodies (PMI<3h). The contamination occurred for 2 min as well as 10 min without any direct contact between the carpet and the corpse. Comparative searches by the dogs were performed over a time period of 65 days (10 min contamination) and 35 days (2 min contamination). The results of this study indicate that the well-trained cadaver dog is an outstanding tool for crime scene investigation displaying excellent sensitivity (75-100), specificity (91-100), and having a positive predictive value (90-100), negative predictive value (90-100) as well as accuracy (92-100).

Using dogs for tiger conservation and research

Article

Dec 2010
Integr Zool

Linda L. Kerley

This paper is a review of the history, development and efficacy of using dogs in wildlife studies and considers the use of dogs in the research and conservation of wild tigers (Panthera tigris Linnaeus, 1758). Using scat detection dogs, scent-matching dogs, law enforcement detection dogs and protection dogs are proven methods that can be effectively used on tigers. These methods all take advantage of the dog's extremely evolved sense of smell that allows them to detect animals or animal byproducts (often the focus of tiger studies). Dogs can be trained to communicate this information to their handlers.

Development of a Dynamic Headspace Concentration Technique for the Non-Contact Sampling of Human Odor Samples and the Creation of Canine Training Aids

Article

Lauryn DeGreeff

Human scent and human remains detection canines are used to locate living or deceased humans under many circumstances. Human scent canines locate individual humans on the basis of their unique scent profile, while human remains detection canines locate the general scent of decomposing human remains. Scent evidence is often collected by law enforcement agencies using a Scent Transfer Unit, a dynamic headspace concentration device. The goals of this research were to evaluate the STU-100 for the collection of human scent samples, and to apply this method to the collection of living and deceased human samples, and to the creation of canine training aids. The airflow rate and collection material used with the STU-100 were evaluated using a novel scent delivery method. Controlled Odor Mimic Permeation Systems were created containing representative standard compounds delivered at known rates, improving the reproducibility of optimization experiments.Flow rates and collection materials were compared. Higher air flow rates usually yielded significantly less total volatile compounds due to compound breakthrough through the collection material. Collection from polymer and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in the trapping and releasing of compounds. The weave of the material also affects compound collection, as those materials with a tighter weave demonstrated enhanced collection efficiencies. Using the optimized method, volatiles were efficiently collected from living and deceased humans. Replicates of the living human samples showed good reproducibility; however, the odor profiles from individuals were not always distinguishable from one another. Analysis of the human remains samples revealed similarity in the type and ratio of compounds. Two types of prototype training aids were developed utilizing combinations of pure compounds as well as volatiles from actual human samples concentrated onto sorbents, which were subsequently used in field tests. The pseudo scent aids had moderate success in field tests, and the Odor pad aids had significant success. This research demonstrates that the STU-100 is a valuable tool for dog handlers and as a field instrument; however, modifications are warranted in order to improve its performance as a method for instrumental detection.

Variables affecting the collection and preservation of human scent components through instrumental and biological evaluations

Article

Davia Tamar Hudson

In certain European countries and the United States of America, canines have been successfully used in human scent identification. There is however, limited scientific knowledge on the composition of human scent and the detection mechanism that produces an alert from canines. This lack of information has resulted in successful legal challenges to human scent evidence in the courts of law. The main objective of this research was to utilize science to validate the current practices of using human scent evidence in criminal cases. The goals of this study were to utilize Headspace Solid Phase Micro Extraction Gas Chromatography Mass Spectrometry (HS-SPME- GC/MS) to determine the optimum collection and storage conditions for human scent samples, to investigate whether the amount of DNA deposited upon contact with an object affects the alerts produced by human scent identification canines, and to create a prototype pseudo human scent which could be used for training purposes. Hand odor samples which were collected on different sorbent materials and exposed to various environmental conditions showed that human scent samples should be stored without prolonged exposure to UVA/UVB light to allow minimal changes to the overall scent profile. Various methods of collecting human scent from objects were also investigated and it was determined that passive collection methods yields ten times more VOCs by mass than active collection methods. Through the use of polymerase chain reaction (PCR) no correlation was found between the amount of DNA that was deposited upon contact with an object and the alerts that were produced by human scent identification canines. Preliminary studies conducted to create a prototype pseudo human scent showed that it is possible to produce fractions of a human scent sample which can be presented to the canines to determine whether specific fractions or the entire sample is needed to produce alerts by the human scent identification canines.

The Differentiation of the Volatile Organic Signatures of Individuals Through SPME-GC/MS of Characteristic Human Scent Compounds

Article

Dec 2009
J FORENSIC SCI

Human scent evidence is utilized as an investigative tool through canine scent discriminations based on the premise that human scent is an individualizing characteristic. This study describes the development of what is effectively a human scent barcode consisting of the relative ratios of an individual's "primary odor" compounds utilized to determine a reproducible and individualizing profile which can be stored in a searchable database for a proof of concept of human scent as a biometric measure. Triplicate hand odor samples were evaluated from 10 subjects utilizing solid phase micro-extraction gas chromatography/mass spectrometry (SPME-GC/MS) and compared via Spearman Rank Correlations. Narrowing the compounds considered for each subject to only those common in all three samples, or a subject's "primary odor constituents," produced a greater degree of both individualization and discrimination; at both correlation thresholds of 0.9 and 0.8, the individuals were correctly discriminated and identified in 99.54% of the cases.

The effect of aging on crime scene objects on the results of scent identification line-ups using trained dogs

Abstract

No full-text available

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