Pseudo-operational trials of Lumicyano solution and Lumicyano powder for the detection of latent fingermarks on various substrates

The author's final peer reviewed version can be found by following the URI link.This study presents pseudo-operational trials comparing a one-step fluorescent cyanoacrylate process with a number of other enhancement techniques on a variety of substrates. This one-step process involves a product, 4% Lumicyano, which is a solution consisting of 4% by weight of a powdered dye (Lumicyano powder) dissolved in a cyanoacrylate-based solution (Lumicyano solution). The cyanoacrylate in the Lumicyano solution may be of a higher quality than that used in the two-step products. One hundred items were collected from the place of work for each trial. Trial 1 involved a comparison of 4% Lumicyano with the conventional two-step cyanoacrylate fuming-dye staining for the detection of latent fingermarks on plastic carrier bags. Trial 2 assessed the quality of the Lumicyano solution (with no powdered dye) but used in a two-step process with basic yellow 40 (BY40). Trial 1, using 4% Lumicyano powder and traditional cyanoacrylate → BY40 detected a similar amount of fingermarks (~295); however, sequential BY40 treatment (i.e., after 4% Lumicyano) detected an additional 30% marks. Trial 2 resulted in the detection of 565 marks after Lumicyano solution → BY40 in comparison to 489 marks after traditional cyanoacrylate fuming and BY40 staining. Trials 3 through 5 compared 4% Lumicyano, 1,2-indanedione-zinc, and ninhydrin on junk mail, magazines, and cardboard used for food or cosmetic packaging; the detection rate was low for all techniques and substrates. Trial 6 on cardboard packaging using 4% Lumicyano, black iron-oxide powder suspension, and magnetic powder also provided a low detection rate. Trial 7, using 4% Lumicyano → BY40, solvent black 3, and iron-oxide powder suspensions on cardboard packaging from a fast food chain, indicated that 4% Lumicyano → BY40 might be a suitable alternative to solvent black 3 and iron-oxide powder suspensions for suspected greasy marks