Latent fingermark development on fired and unfired brass ammunition under controlled and blind conditions.

There has been growing interest in the Foster+Freeman RECOVER® Latent Fingerprint Technology system to develop fingermarks from fired ammunition. Over a six-month period, 1540 fingermarks were deposited on brass.223 ammunition, the majority of which were then fired after different time intervals. Samples were subjected to a cleaning protocol and/or processed with disulfur dinitride, cyanoacrylate/Brilliant Yellow 40, and/or vacuum metal deposition. Overall, 121 out of 1304 (9.3%) of natural fingermarks deposited were deemed identifiable post-firing and processing. This translated to 102 out of 652 (15.6%) of fired cartridges having identifiable fingermarks. A pseudo-operational study, which involved processing 1000 fired brass ammunition of various caliber using disulfur dinitride with and without a cleaning protocol, was conducted; only 18 (1.8%) comparable fingermarks were developed. This study demonstrates the need for more robust research involving this challenging substrate and novel technology, with which several issues were identified.

Evaluation of multi-target immunogenic reagents for the detection of latent and body fluid-contaminated fingermarks.

Fingermark enhancement reagents capable of molecular recognition offer a highly selective and sensitive method of detection. Antibodies and aptamers provide a high degree of adaptability for visualisation, allowing for the selection of the most appropriate visualisation wavelength for a particular substrate without the need for specialist equipment or image processing. However, the major hurdle to overcome is the balance between sensitivity and selectivity. Single-target molecular recognition is highly specific, purported to have better detection limits than chemical reactions or stains, and can provide information about the donor or activity, but often results in incomplete ridge pattern development. Consequently, the development and evaluation of multi-target biomolecular reagents for fingermark enhancement was investigated, with the focus on endogenous eccrine secretions. To assess the suitability of the immunogenic reagents for potential operational use, a variety of parameters (i.e., processing time, fixing and working solution conditions) were optimised on a wide range of non-porous and semi-porous substrates. The relative performance of immunogenic reagents was compared to that of routine techniques applied to latent marks and marks in blood, semen and saliva. The incorporation of these novel reagents into routine technique sequences was also investigated. The experimental results indicated that the multi-target immunogenic reagents were not a suitable alternative to routine detection methods or sequences, but may have promise as a "last resort" method for difficult substrates or cases.

Evaluation of one-step luminescent cyanoacrylate fuming.

One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster+Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster+Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster+Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples.