The use of liquid latex for detecting traces of blood following thermal exposure.

In cases of crimes involving blood, the perpetrators often attempt to remove the traces they have left behind. Setting fire to the crime scene, aside from cleaning measures, seems to achieve this goal and presents a major challenge for crime scene investigators. There is only very little published information available on the effect of fire and extreme heat on blood and the detection thereof. After exposure to high temperatures of or exceeding 1.000 °C, blood is deemed to be undetectable. This study exposed 11 different potentially crime-relevant objects using a standardized and controlled procedure to temperatures of 300 °C, 700 °C, and 1.000 °C documenting the influence of heat on bloodstains and the detection of blood. The results of the forensic collection of blood traces with and without liquid latex confirmed the advantage of using the latex method. Almost all objects showed a clear luminescence-caused visualization of traces of blood after removing the soot with a latex lift. There were also fewer false positive results than in tests not using latex.