Type and storage of human remains detection canine training aids: A review and handler survey

Abstract

When properly trained, canines are very effective detectors, especially in human remains detection (HRD) and search and rescue (SAR). However, the variability in decomposition odor profiles presents a challenge and requires extensive and adaptable training. Although some protocols and guidelines exist, they do not account for all the possible influential factors leading to inconsistency between organizations. This paper combines a review of research on factors affecting the odor profile of remains with a survey of canine training in the field. Key aspects covered include training aid materials used (e.g. bones, blood, body parts), sample age, containment material, and storage conditions. Findings reveal a consensus amongst handlers and research in some practices, such as use of multiple training aid materials for a variation in odor profiles and use of glass containment to minimize background odor. Discrepancies, however, remain, particularly in the age of sample (fresh vs. very aged), frequency of aid replacement, and storage conditions such as temperature and humidity. The results emphasize the importance of exposing canines to diverse remains odors in differing conditions, providing recommendations for more improved HRD training and directions of future research.

Keywords: Detection canines; Human remains; Human remains detection; Storage; Training aid.

Fig. 1

Certification of HRD canines by location.

Fig. 2

Common certifying organizations. All other organizations mentioned appeared a lower response rates (1 or 2 mentions total).

Fig. 3

Distribution of compound classes detected in human tissues used for training HRD canines. Adapted by Iqbal et al., 's 2017 review from Hoffman et al., 2009 and used with permission [15].

Fig. 4

Distribution of HRD training aid type. This is based on a) total number of responses or b) percentage of responses by location, normalized to the total number of responses from that location. Added categories based on “other” responses are indicated by ∗.

Fig. 5

Average abundance of varying chemical classes of compounds over time; a) displays aldehydes, aromatics, nitrogen containing compounds, and alcohols, while b) displays sulfur containing compounds, esters, hydrocarbons, halogenated compounds, ketones, and phosphorus containing compounds. Adapted from Ueland et al.'s study in 2021 [26].

Fig. 6

Oldest training aid. This data included the total number of responses regardless of location to show the percentage of handlers with their oldest aid being less than 6 months, 6 months to 1 year, 1–2 years, or older than 2 years.

Fig. 7

How often handlers replace training aids. Additional categories than presented in the survey were added based on “other” responses indicated by ∗.

Fig. 8

Training aid containment. Normalized to 100 % based on 188 total responses. Added categories based on “other” responses are indicated by ∗.

Fig. 9

Storage temperatures. Normalized to 100 % based on 188 total responses.

Fig. 10

Storage humidity. Normalized to 100 % based on 188 total responses.

Fig. 11

Storage lighting. Normalized to 100 % based on 188 total responses.