Forensic Applications of Chemical Imaging: Latent Fingerprint Detection Using Visible Absorption and Luminescence

Abstract

Chemical imaging technology is a rapid examination technique that combines molecular spectroscopy and digital imaging, providing information on morphology, composition, structure, and concentration of a material. Among many other applications, chemical imaging offers an array of novel analytical testing methods, which limits sample preparation and provides high-quality imaging data essential in the detection of latent fingerprints. Luminescence chemical imaging and visible absorbance chemical imaging have been successfully applied to ninhydrin, DFO, cyanoacrylate, and luminescent dye-treated latent fingerprints, demonstrating the potential of this technology to aid forensic investigations. In addition, visible absorption chemical imaging has been applied successfully to visualize untreated latent fingerprints

Spectroscopic Imaging of Latent Fingermarks Collected with the Aid of a Gelatin Tape

“…[2][3][4][5][6][7][8] The application of ATR-FT-IR imaging for the study of the chemical composition of various residues contained in adult fingerprints was demonstrated by Ricci et al 9 At crime scenes, marks developed on textured or patterned backgrounds may be difficult to visualize in situ, and therefore, it may be desirable to collect fingermarks from crime scenes so that they can be transported for further examination in a laboratory or in a fingerprint bureau. Traditionally, many fingermarks are developed at crime scenes by powdering (e.g., with aluminum flake powder) and are recovered for subsequent evaluation by lifting them from the surface on clear adhesive tape.…”

Chemical Sensing and Detection in Forensic Science

“…Such light sources are generally more versatile than lasers because of the wide range of wavelength bands that are available (compared to the limited number of laser lines that are typically available with laser-based systems). More recently, chemical imaging systems have been investigated for the visualization of treated latent fingermarks [115,116]. While this approach can provide significant advantages for weak marks and those on highly luminescent backgrounds, it is a very specialized technique that is generally not available to operational laboratories for routine use.…”

Using spectral information in forensic imaging

“…The possibility of using chemical spectral information to enhance forensic images has been discussed in several recent publications [1][2][3]. These methods rely on forensic evidence or enhancement reagents having distinctive spectral signatures, which are different from the background.…”

“…These methods rely on forensic evidence or enhancement reagents having distinctive spectral signatures, which are different from the background. With the more advanced methods such as principal components analysis this difference can be subtle [1], but in general the more different the analyte from the background the easier it will be to differentiate the two. To this end we have been examining the spectral properties of forensic enhancement agents, with a view to increase the utility of these imaging techniques.…”