Forensic bruise documentation with alternate light sources: Preliminary observation on deceased individuals in a routine illuminated autopsy setting

Alternate light sources (ALS) have been suggested to improve bruise visibility for medicolegal evaluations. Previous studies have recommended darkened conditions; however, this does not reflect real-life autopsy settings, where multiple examinations are conducted simultaneously and turning off the lights is neither practical nor safe. This study evaluated the use of ALS for documenting bruises under normal lighting conditions without altering the autopsy setup. We photographed 161 bruises (99 recent, 62 non-recent) using CrimeLite® AUTO (Foster+Freeman) under common white light (CWL), violet ALS with 415 nm long-pass (VLP), violet ALS with 415 nm band-pass (VBP), and blue ALS with 445 nm long-pass (BLP). Bruises were classified as recent or non-recent based on the presence of yellow coloration. Visibility was scored using a "modified" Bruise Visibility Scale (BVS), and surface area was measured. Observer variability was assessed using Cohen's kappa (κ) and intraclass correlation coefficients (ICC); logistic and Cox regression analyses were performed to evaluate BVS and size across lighting sources. We found that ALS did not enhance bruise visibility compared to CWL. VBP and BLP reduced visibility, while VLP showed occasional improvements but without statistical significance. Surface area measurements indicated that VLP visualizes bruises with larger dimensions than under CWL, whereas BLP and VBP did not. Observer agreement for the four BVS categories yielded κ values ranging from moderate to substantial, while ICCs showed excellent agreement for surface-area measurements for most light sources. Despite its limitations, the study suggests that ALS, particularly VLP, may have potential utility for bruise documentation under normal lighting conditions.