<p>Forensic identification in advanced decomposition body is challenging when traditional methods become unreliable. This case report demonstrates the utility of 3D modeling of the frontal sinus for human identification in forensic anthropology and odontology. A decomposed body found in southern Brazil was successfully identified using 3D-2D superimposition technique, which overlays a three-dimensional model derived from antemortem computed tomography (CT) data onto postmortem radiographs. The frontal sinus, with its unique morphological patterns, served as a reliable anatomical marker for comparison. This cost-effective approach utilizing open-source software addresses the need for accessible identification methods in resource-limited forensic settings. The technique demonstrates superior accuracy compared to traditional 2D radiographic methods while remaining practical for institutes with limited imaging technology. Our findings supporteas the application of 3D-2D superimposition and highlight the importance of forensic experts training in 3D forensic imaging technology for enhanced human identification capabilities.</p>