Letter to editor regarding article: "A continuous forensic spectral analysis study to identify antemortem and postmortem muscle contusions by chemometrics".

This letter provides a critical analysis of the translational pathway for the innovative FTIR spectroscopy methodology proposed by Wang et al. (2025) to differentiate antemortem from postmortem muscle contusions. While the reported 92% accuracy in a controlled rodent model is commendable, its direct applicability to complex human forensic casework remains unsubstantiated. This correspondence identifies three critical barriers to court-admissible adoption: the significant biological and taphonomic divergence between rodent models and human cadavers, the unvalidated robustness of spectral biomarkers against real-world confounders such as pre-existing disease states and environmental contaminants (e.g., soil, decomposition byproducts), and the complete absence of a validation step on human tissues with known trauma vitality. The spectral signatures resulting from proteins and phospholipids present, central to the proposed model, are highly susceptible to alteration by these uncontrolled variables, risking erroneous vitality assessment. The Partial Least Squares-Discriminant Analysis (PLS-DA) model's performance against such "spectral noise" is a pivotal, yet unaddressed, determinant of its practical utility. Therefore, while the research marks a significant step forward, we argue that its limitations must be explicitly acknowledged to guide future research effectively. We conclude that the mandatory next steps must involve rigorous external validation on human tissue samples and systematic stress-testing of the model against a comprehensive range of physiological and environmental variables to ensure its reliability, forensic rigor, and eventual judicial reliability under admissibility standards such as Daubert.