Use of luminol and ultraviolet fluorescence methods for estimation of time of death from bone tissue

Accurate estimation of the time since death presents a persistent challenge in forensic investigations, particularly in advanced decomposition or skeletonization. Traditional visual and morphological assessments are often limited by environmental variability and taphonomic factors. This study aimed to assess the applicability of ultraviolet (UV) fluorescence and luminol-based chemiluminescence analyses for estimating the time since death from skeletal remains and evaluate their potential integration into routine forensic practice. A total of 58 adult skeletal cases with known time of death and identity were analyzed. Ultraviolet fluorescence imaging was performed using a 365 nm light source and analyzed in Adobe Photoshop to quantify blue fluorescence, employing both custom and literature-based RGB color codes. Bone powder was subsequently obtained using a Dremel 3000 device, and luminol chemiluminescence was quantified with a Fluoroskan FL Microplate Luminometer, following standard luminol preparation protocols. While both UV fluorescence and luminol chemiluminescence produced measurable signals, neither method independently demonstrated a reliable or consistent correlation with the time since death. Environmental factors and taphonomic variables, including deposition context and scavenger activity, significantly influenced the outcomes. UV fluorescence and luminol analyses demonstrate potential supplementary value in forensic skeletal assessment but are insufficient as standalone methods for the estimation of the time since death. Future studies should expand sample sizes, particularly for PMIs exceeding 30 years, and incorporate detailed taphonomic context to enhance accuracy.