Research on correlation between DNA typing and trace characteristics of blood after thermal exposure.

The identification of biological evidence is particularly important for criminal detection, and the deoxyribonucleic acid (DNA) analysis plays a significant role in reconstructing events. However, bloodstains after thermal exposure in fires are quite unique compared to those in other scenes. Previous results regarding DNA recovery in bloodstains after heating are inconsistent with each other, which limits guidance for forensic science.

Study on the methods of visualizing bloodstains after thermal exposure.

To establish the correlation between thermal conditions imposed on bloodstains and visualizing effect of enhancement techniques, infrared photography and four chemical enhancement reagents were used to visualize bloodstains following thermal exposure. A black tile was selected as the substrate to intensify the visualization challenge, with a Cone Calorimeter serving as the standardized heating source to control thermal conditions. Compared with standard photography, infrared photography is proven to be a valuable complement to chemical reagents, showing significant advantages in visualizing bloodstains after thermal exposure.