Exploring chemical traces of sharp force trauma in burned bone through SEM-EDS: A pilot study

Sharp force trauma (SFT) is a leading cause of homicide-related deaths, frequently involving kitchen knives as weapons. Offenders may attempt to eliminate forensic evidence by burning a corpse, complicating medicolegal investigation. While scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) has successfully detected metallic traces from sharp objects in skin and fresh bone, its efficacy in burned bone is currently unexplored. This study aimed to evaluate the potential of SEM-EDS to detect metallic residues transferred from sharp tools to bone that was subsequently burned, thereby contributing to the development of an identification procedure in forensic investigation. Ten knife strikes were inflicted on fleshed porcine ribs, which were then burned in an electric muffle furnace at 700 °C for two hours. Sharp lesions were analyzed using SEM-EDS to identify transferred chemical elements. Traces of iron and chromium were detected in seven lesions, with silicon identified in two samples. These elements, absent from the control samples, provided robust evidence of transfer from the blade to the bone. The residues appeared as bright spots with either undefined shapes or well-defined particles, located along the lesion edges. This study is the first to confirm the identification of metallic traces from SFT in bone subsequently exposed to heat using SEM-EDS. Despite thermal exposure, residues persist and remain detectable. SEM-EDS analysis is thus a non-destructive, valuable technique for distinguishing heat-induced bone damage from SFT. Further research with a larger sample and a broader range of implements is needed to validate and extend these findings for forensic applications.