ABSTRACT
The efficacy of Gold/Zinc and Silver/Zinc vacuum metal deposition (VMD) protocols were assessed as stand-alone methods of fingermark enhancement on ballistic brass materials. The results demonstrate the effectiveness of VMD enhancement on a large pool of donors (n = 20), with potentially identifiable marks recovered for the majority of donors, including samples aged up to two months. Of the 20 donors a subset of six donors were selected to assess the capability of VMD enhancement on brass fired cartridge cases, from which some friction ridge detail (FRD) was recovered. Lastly, an attempt to understand which fingermark components are facilitators of VMD enhancement was made. Fingermark residue was extracted from brass tiles and fired cartridge cases before analysing chromatographically (GC-MS). Although some key components were indicated, further evaluation of all fingermark components is needed to draw firm conclusions as to the role each plays in VMD enhancement.
ABSTRACT
In order to assess the efficacy of vacuum metal deposition (VMD) as a technique to develop fingermarks on ballistic metallic surfaces, a preliminary study using six donors (three male & three female) was conducted. Using a sequential metal deposition process, two metal combinations were studied-gold/zinc and silver/zinc. Results indicate the potential of this technique, by developing identifiable fingermarks on brass metal disks aged from a few days up to more than a month old. As the development of fingermarks on fired (brass) cartridge cases is an area of interest, a further study was conducted where a total of 20 fingermarks were deposited on cases. After firing, second level fingermark characteristics were successfully observed on cartridge cases highlighting its potential as a fingermark enhancement method for ballistic brass materials. Further work is required to fully evaluate the VMD process and its reliability as a fingermark enhancing method on ballistic surfaces.
ABSTRACT
There are many different fingermark visualization techniques available, and the choice of methodology employed may be dependent on the surface type. This comprehensive review of the scientific literature evaluates the methodologies of fingermark enhancement methods that are applicable to metallic surfaces; optical, physical, chemical, and physicochemical methods are critically discussed. Methods that are currently used and those that have the potential to reduce the cost and time required to process evidence and increase the recovery rates are considered and are assessed against the Centre for Applied Science and Technology (CAST) and the International Fingerprint Research Group (IFRG) guidelines. The use of chemical imaging techniques in particular has increased the potential to recover fingermarks of sufficient quality for identification purposes. Presently, there appears to be a lack of detailed research pertaining to validation and thorough casework studies for fingermark enhancement techniques. Further studies incorporating these guidelines are recommended.
