Effect of carrier solvent in 1,2-indanedione formulation on the development of fingermarks on porous substrates

As an important technique for the detection of fingermarks on porous surfaces, 1,2-indanedione is widely used due to its excellent detection performance. In order to optimize the effectiveness of 1,2-indanedione, several institutions have modified the original formulation. In this study, four different 1,2-indanedione formulations were used to treat fingermarks deposited on different porous substrates to determine the most suitable formulation and whether Solstice-PF can be an alternative carrier solvent for the currently used HFE7100. It was found that the Solstice-PF-based formulation performed similarly to the HFE7100-based formulation on copy paper, but when treating fingermarks deposited on brown paper and newspaper, Solstice-PF was superior to HFE7100 by developing up to 10% more marks graded 3 and 4 regardless of the ageing period. The results confirm that Solstice-PF can be used as an alternative carrier solvent for 1,2-indanedione formulations with good detection rates and lower costs.

The effect of mark enhancement techniques on the subsequent detection of semen/spermatozoa

Fingermarks, footwear marks, blood and semen are amongst the most commonly encountered types of evidence at crime scenes. Previous work has extensively investigated fingermark and blood enhancement techniques and a sequence developed to maximise evidence recovery; however, there is limited research as to the effect of these techniques on the subsequent detection of body fluids such as semen. In this study, seven fingermark and blood enhancement techniques (e.g. powder suspension, cyanoacrylate fuming and acid violet 17) were employed followed by the subsequent detection of semen/spermatozoa. Other variables included in the study were the use of two substrates (white ceramic tiles and grey laminate flooring), a depletion series and ageing periods of 1, 7, 14 and 28 days. The effect these techniques had on the subsequent detection of semen was assessed by visual and fluorescence examination followed by presumptive and confirmatory testing for semen and spermatozoa. The results found that protein stains (acid violet 17 and acid yellow 7) caused a loss in presumptive test reactivity; however, sperm heads were still observed using microscopic examination after extraction and staining. The use of black magnetic powder, Bluestar(®) Forensic Magnum luminol, Lumicyano™ 4% and cyanoacrylate fuming followed by basic yellow 40 staining did not hinder subsequent presumptive and confirmatory tests for semen and sperm heads. Powder suspension caused a loss in both presumptive test reactivity and sperm heads from the substrate. In general, the enhancement techniques resulted in the improved visualisation of the semen stains under white and violet/blue light. The results from this study aim to provide a strategy to maximise evidence recovery and improve efficiency in an integrated forensic approach.