Non-invasive forensic identification of excavated human remains: capturing surface and internal fingerprints using optical coherence tomography.

Unidentified human remains are frequently found in missing person cases, necessitating identification for forensic purposes and to inform the next of kin. Traditional postmortem fingerprinting methods depend on intact surface fingerprints, which are often compromised by decomposition. A viable alternative is to use internal fingerprints (a blueprint of the surface fingerprint located just below the epidermis) instead. This study assessed the utility of Optical Coherence Tomography (OCT) as a means to record internal fingerprints from excavated human fingers. Conducted at the Amsterdam human taphonomic test site, the investigation comprised two longitudinal studies and two in situ burial scenarios. Human fingers were buried, excavated, and scanned using OCT at various time intervals. Internal fingerprints could be recorded up to 7 days longer than surface fingerprints, with a maximum of 10 days post-burial. These internal fingerprints provided higher minutiae counts, suitable for Automated Fingerprint Identification System (AFIS) searches. Additionally, in one case, fingerprints were successfully extracted after 13 weeks and 10 months of in situ burial. This demonstrates OCT's potential to enhance postmortem fingerprinting for identifying human remains in forensic investigations.