Latent prints are hidden prints that can be found at crime scenes. According to the Federal Bureau of Investigation (2006), latent prints include fingers, palms, and soles. These surfaces bear sweat pores that secrete moisture that can linger on various surfaces for extended periods (Federal Bureau of Investigation, 2006). This discussion post will examine latent print residue composition as well as its viability under different conditions.
The latent print residue consists of both organic and inorganic components. The organic elements refer to the human swear secretion, primarily apocrine, eccrine, and sebum, originating from different types of sweat glands (Boseley et al., 2019). Inorganic matter found in the latent print residue can include amino acids, trace metals, proteins, and ions secreted with sweat (Boseley et al., 2019). In addition, other contaminants can be present, depending on the activities undertaken before the prints are left on the examined surface. For example, food residue, cosmetics, powders, dust, and skin cells can be part of the composition of latent prints (Khare & Singla, 2022). Each latent print residue is unique; therefore, their viability may differ.
The viability of latent prints depends on the residue composition and other factors, such as surface, weather, and time passed since the print was left. Thus, latent prints are absorbed differently by different surfaces. According to Khare and Singla (2022), porous and semi-porous surfaces such as cardboard and finished wood can absorb organic matter from the surface of fingers, palms, or soles. Latent print residue on such surfaces can remain for long periods. Meanwhile, non-porous surfaces, including glass, plastics, and ceramics, do not absorb residue, and prints on such surfaces do not last more than a few days (Khare & Singla, 2022). Moreover, high environmental temperatures can impact organic matter in print residues, leading to them disappearing faster (Khare & Singla, 2022). In addition, adult and child latent prints fade away at different rates, with child fingerprints evaporating faster than those of adults due to a different organic structure (Khare & Singla, 2022). Concerning time, depending on the composition, surface, and environmental conditions, latent prints can remain on surfaces for decades. In summary, latent print residue comprises organic, inorganic, and other matter affecting the viability of such imprints.
References
Boseley, R., Dorakumbura, B., Howard, D. L., De jonge, M., Tobin, M. J., Vongsvivut, J., Ho, T., Van Bronswijk, W., Hackett, M. J., & Lewis, S. (2019). Revealing the elemental distribution within latent fingermarks using synchrotron sourced X-ray fluorescence microscopy. Analytical Chemistry, 91(16), 10622–10630.
Federal Bureau of Investigation. (2006).The science of fingerprints: Classification and uses.
Khare, V., & Singla, A. (2022). A review on the advancements in chemical examination of composition of latent fingerprint residues.Egyptian Journal of Forensic Sciences, 12(1), 1–9.