Fingermark identification remains one of the most important and unambiguous approaches to place perpetrators at crime scenes. While a great number of forensic techniques for the visualization of latent marks already exist, they all suffer from one or more shortcomings such as: limited applicability with regard to the age of a mark or the nature of the surface it was deposited on ("substrate"); the requirement of expensive laboratory equipment and special training; and the potential to alter or even destroy evidence, or at least leave a visible record of their application.
The goal of this project was to develop and validate novel fingermark lifters, which allow instantaneous, on-the-spot visualization of marks. The underlying detection principle used with these lifters is based on the reaction of either pH-sensitive or amine-reactive substances - immobilized on suitable solid supports such as membranes - with chemicals contained in fingermark residues (e.g., lactic acid, amino acids, proteins, and amino sugars). The exposure of appropriate reagents to such an environment causes a change in their spectroscopic properties, which can be seen, depending on the type of reagent, either under ambient or luminescent light conditions.
