The detection and recovery of latent fingerprints on clothing and fabric items

Fingermarks recovered on fabrics from a crime scene can support the three aspects of forensic investigations; identification of the individuals involved and their association to each other and assist in reconstruction of the sequence of events. Currently, there are no recognized and generally accepted methods for the enhancement of fingerprints on fabrics due to the nature of the fabric composition. Cyanoacrylate fuming has been utilized in studies in fingerprint recovery on fabric. This method has proven to be effective for developing latent fingerprints on dark colored fabrics. On light-colored fabrics, the desired contrast isn't achieved as the CA developed prints appear as a whitish deposit. Post-treatment of CA fumed prints with fluorescent dye staining may improve the contrast, but it causes excessive background staining on the fabrics to surface. Cyanoacrylate fuming followed by Fourier transform infrared spectroscopy (CAF/FT-IR) has been proven to be the most successful method in enhancing finger-marks on smooth and shiny fabrics like silk, polyester, and nylon. However, the technique has drawbacks; time-consuming and the CA monomer selectively polymerized onto the friction ridges of the fingerprint on some fabrics but the challenges raised from obtaining contrast of prints developed on light-colored and pattern fabrics. Vacuum metal deposition has been utilized in studies in fingermark recovery on fabrics. Gold/zinc VMD developed fingermarks with great ridge detail on smooth and non-porous fabrics such as nylon whereas on rough and porous fabrics such as cotton, empty prints, and impression, rather than ridge details were visible. Silver VMD proved to be effective on polyester as it developed high-quality fingermarks that were attributed to the smooth, shiny and less porous tight weave of the fabric which helped retain the fingermark deposit. Silver VMD has proven to be effective for developing latent fingermarks on dark-colored fabrics and has an advantage over gold/zinc VMD in that marks visualized are light in color which contrasts well against the dark background, allows for assessment of the manner in which the fabric was touched, either by grab or press method and enables acquisition of touch DNA for identification purposes. One step fluorescent cyanoacrylate, Lumicyano™ has proven to be effective in developing fresh latent fingermarks on dark-colored clothing fabrics. High-quality fingermarks were obtained on synthetic fabrics (polyester and nylon) than natural fabric (cotton and polycotton). This is attributed to the less absorbent (more hydrophobic) nature of synthetic fabrics than natural fabrics, thus the fingerprint residues would remain on the surface of the synthetic fabric for a longer period. The aim of these studies was to investigate the effect of donor, fabric type, mark age and method of fingermark deposition on the quality of marks visualized using silver VMD, Lumicyano™, gold/zinc VMD, CAF & FT-IR, and CAF & iron oxide/carbon powder suspensions. KEYWORDS Vacuum metal deposition (VMD), Cyanoacrylate fuming (CAF), Lumicyano ™, Fingermarks, Fingermark enhancement, Fabrics, Palmar flexion creases, and Ridge detai