Visualization of latent fingermarks on fabric using multi-metal deposition (MMD)-A preliminary study

Multi-metal deposition (MMD) is a versatile fingermarks detection technique adapted from the colloidal gold biolabeling. However, the tedious procedures of MMD makes it receive little attention compared with other methods. The aim of this study is to evaluate the efficacy of MMD technique on several common fabrics, which is considered notoriously challenging for latent fingermark detection. Four different MMD formulations were examined to process fingermarks deposited on nylon taffeta, polyester taffeta, polyester pongee and cotton sateen to determine the most suitable one and the influence of aging and water immersion were also determined through subsequent experiments. It was found that MMD I outperformed other three formulations and obtained excellent results on nylon taffeta, polyester taffeta and satin ribbon, with polyester taffeta and satin ribbon providing more than 30% of identifiable marks even for fingermarks aged over 28 days. Cotton sateen and oxford cloth failed to produce ridge details but evidence of "touch" were successfully visualized, which may contribute to further DNA extraction. Water immersion did have some observable influence on the quality of detected marks as part of the MMD reactant within fingermarks lost during immersion, but the result from nylon taffeta and satin ribbon is still satisfying with the percentage of marks scored 3 and 4 reached 30%. The result of this study confirmed the capability of MMD I in treated with fingermarks on several kinds of fabrics, and shows potential to promote this non-instrumentation dependent technique.