Post-mortem to ante-mortem facial image comparison for deceased migrant identification

The identification of deceased migrants is a global challenge that is exacerbated by migration distance, post-mortem conditions, access to ante-mortem data for comparison, inconsistent international procedures and lack of communication between arrival and origin countries. Due to low technology requirements, fast speed analysis and ease of transferring digital data, facial image comparison is particularly beneficial in those contexts, especially in challenging scenarios when this may be the only initial ante-mortem data available to identify the deceased. The Facial Identification Scientific Working Group (FISWG) professional guidelines for facial image comparison were developed for living facial appearance, and, therefore, a tailored protocol for the application of post-mortem to ante-mortem facial image comparison was proposed and evaluated in this research. The protocol was investigated via an inter-observer and an accuracy study, using 29 forensic cases (2001-2020) from the University of Milan, provided by the Laboratory of Forensic Anthropology and Odontology. In order to replicate a migrant identification scenario, each post-mortem subject was compared to all 29 ante-mortem targets (841 comparisons). The protocol guided the practitioner through stages of facial image comparison, from broad (phase 1) to more detailed (phase 3), eventually leading to a decision of 'exclusion' or 'potential match' for each post-mortem to ante-mortem case (phase 4). In phase 4, a support scale was also utilised to indicate the level of confidence in a potential match. Each post-mortem subject could be recorded with multiple potential matches. The protocol proved to be useful guide for facial image comparison, especially for less experienced practitioners and the inter-observer study suggested good reproducibility. The majority (82-96%) of ante-mortem subjects were excluded at the first stage of the protocol, and 71 full post-mortem to ante-mortem facial image comparisons were carried out. On average, two or three potential matches were recorded for each post-mortem subject. The overall accuracy rate was 85%, with the majority (79%) of ante-mortem non-targets correctly excluded from the identification process. An increased number and quality of available ante-mortem images produced more successful matches with higher levels of support. All potential matches involving non-targets received low levels of support, and for 73% of the post-mortem subjects, the ante-mortem target was the only recorded potential match. However, two ante-mortem targets were incorrectly excluded (one at the first stage of the protocol) and therefore changes to the protocol were implemented to mitigate these errors. A full protocol and a practical recording chart for practitioner use is included with this paper

Critically Envisioning Biometric Artificial Intelligence in Law Enforcement

This report presents an overview of the Critically Exploring Biometric AI Futures project led by the University of Edinburgh in partnership with the University of Stirling. This short 3-month project explored the use of new Biometric Artificial Intelligence (AI) in law enforcement, the challenges of fostering trust around deployment and debates surrounding social, ethical and legal concerns

Critically Envisioning Biometric Artificial Intelligence in Law Enforcement

This report presents an overview of the Critically Exploring Biometric AI Futures project led by the University of Edinburgh in partnership with the University of Stirling. This short 3-month project explored the use of new Biometric Artificial Intelligence (AI) in law enforcement, the challenges of fostering trust around deployment and debates surrounding social, ethical and legal concerns

AM-PM facial image comparison for forensic human identification

The uniqueness of the face has been studied concerning its application for human identification. In particular, morphological facial comparison has been used to verify the identities of living individuals in forensic investigations and has received considerable attention, including validation studies and the development of international guidelines (FISWG, 2019a; Bacci et al., 2021b). At the same time, the application of morphological comparison in post-mortem identification has been recognised (Olivieri et al., 2018; Cappella et al., 2021), but remains understudied and require further validation. In light of this, this study investigates the reliability of morphological facial comparison using an unconstrained sample of ante-mortem (AM) and post-mortem (PM) images of recent deceased (N=29), and aims to develop a methodological protocol combining the structure of the living individual's guidelines and accounts for the early post-mortem changes that affect the face. The reliability of the morphological method for PM identification is investigated by performing the comparisons and documenting the process using the protocol, and by testing it with three observers on selected AM-PM pairs (N=15). The key findings suggest that AM-PM photographic comparison using the proposed protocol could help to narrow down the potential matches of a PM subject. Moreover, in some cases, it is also possible to provide a single correct AM target for a PM subject with a high level of confidence. While the validity of the protocol requires further investigation beyond this study, its design, which includes the addition of a stage for analysis of the decomposition changes affecting the PM subjects and a holistic preliminary analysis of AM-PM pairs to exclude the obvious non-matches, seems advantageous. The interobserver study results indicate that both absolute agreement (ICC=0.813) and agreement on the level of support (Kendal’s K=0.885) are satisfactory. Overall, the limitation of the study includes the small interobserver random sample (15 pairs), the absence of non-matching AM subjects in the sample pool tasks, and presence of a very limited number of PM subjects showing signs of post-mortem changes (e.g. facial bloating). This study could benefit forensic casework, in particular in the Disaster Victim identification (DVI) procedures, when other AM primary identifiers are scarce. Future studies should investigate the application of PM photographic facial comparison using a larger database simulating an open disaster scenario, while also further validating and testing the applicability of the developed method with different observers