Fluorescent chemical development of latent fingerprints

Kristen A. Smith
Fingerprints are crucial pieces of evidence that can be used both for identification purposes but also to exonerate those people who have been wrongfully convicted. When fingerprints are found at crime scenes, seldom are they presented in an "ideal" manner. Most are partial, distorted, compromised, or a combination of all three. The usefulness of recovered fingerprints depends on their ability to be recovered and enhanced without disruption of the original detail, while also enhancing that
more » ... l. Fluorescent reagents are typically used to recover these marks, especially from objects with poor background contrast or from objects that have been compromised (e.g., submerged in water, exposed to extreme weather, damaged by fire, etc.) They allow for greater visual enhancement in marks that would otherwise be "invisible". Fluorescent reagents typically work best with latent fingerprints, prints that have been left in the sebum (oil) or sweat present on the fingertips. In order for fluorescent fingerprints to be made visible, they must be viewed under the stimulation of an alternative light source and with a viewing filter. Rhodamine B, a fluorescent chemical and biological staining agent, along with several other components, was used in this study to create a novel formulation of a fluorescent fingerprint powder. The powder was tested on latent fingerprints that were deposited on nonporous objects. The latent fingerprints were deposited as a "loaded series" or as a "depletion series". The novel formulation was able to recover both sebum-rich and eccrine-rich latent fingerprints from nonporous objects with strong detail, though the powder showed better detail and enhancement capabilities with the sebum-rich fingerprints. The detail was greater in the loaded sebum-rich series, but good detail as able to be recovered in the depletion-series, as well. The powder exhibited strong fluorescence across all samples. Further studied should be conducted to determine the reproducibility and sensitivity of this novel powder, but [...]
doi:10.7282/t3-0prv-na10 fatcat:mjucv7tmtzft7lwjz5kjjwgy5a