The use of mantrailing dogs in police and judicial context, future directions, limits and possibilities - A law review.

The extraordinary capabilities of the canine nose are increasingly being used by law enforcement agencies in many countries to solve and reconstruct crimes. As a result, this type of forensic evidence can be and is still being challenged in the courts. So far, only a few publications have addressed the jurisprudence concerning mantrailing. We provide an overview of the jurisprudence in Germany and the USA, as well as insights from France. Relevant databases were searched, and 201 verdicts from Germany and 801 verdicts from the USA were analyzed. As a result, 16 published verdicts on the topic of mantrailing were found for Germany, and 44 verdicts since 2010 were found for the USA. The use of mantrailers and human scent discrimination dogs is employed in the investigative process in all three countries. The results derived from these methods are admissible as evidence in court, albeit not as sole evidence.

Scent lineups compared across eleven countries: Looking for the future of a controversial forensic technique.

A scent lineup is generally a procedure whereby a dog's alerting behavior is used to establish that the dog detects two scents, one from a crime scene and one from a suspect, as deriving from the same person. The aim of this article is to compare methodologies of using dogs in scent lineups as a means of identifying perpetrators of crimes. It is hoped that this comparative approach, looking at countries where the method is currently or has in the past been used, will help determine what issues should be addressed in order to assure that the scent lineup will have a future as a forensic technique. Participants from eleven countries-Belgium, The Czech Republic, Finland, France, Germany, Hungary, Lithuania, The Netherlands, Poland, Russia, and the U.S.-completed a survey questionnaire regarding key aspects of the scent lineup procedures used by the police in their countries. Although there was broad overlap on certain matters, such as the use of control and zero trials, collection of decoy scents from individuals of similar gender and race as the suspect, materials for holding scent, frequency of cleaning and changing stations, and use and timing of rewards, there were significant differences in the degree of blindness required, who calls an alert (handler or experimenter), and whether handlers can work with more than one dog. The gap between recommendations and results available from the scientific literature and procedures used in police practice was greater for some countries than others, even taking into account that some scientific methodologies might be expensive or impractical given agency resources. The authors make recommendations about how to go forward if scent lineups are to remain a valid forensic technique.

Individual human scent as a forensic identifier using mantrailing.

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.