Time is Money or Money is Time? A Rapid Operational Sequence for Detecting Fingermarks on Polymer Banknotes

Abstract

Banknotes are often found in high‐profile crimes such as armed robberies, bribery, and terrorist activity. However, such exhibits present a challenge to forensic operatives regarding fingermarks development, due to their mass quantities, potential for fingermarks on both sides, and their unique complex background in terms of color, irregular patterns, and topography. Hence, the standard development protocols become inefficient, due to the difficulty in achieving high contrast images over the background. This study focused on finding an operational sequence that would minimize the time of work on polymer banknotes, in terms of both development and image processing. Thirty‐two fingermarks were developed by vacuum metal deposition (VMD), black magnetic powder, and cyanoacrylate fuming (CA) followed by visualization and imaging by reflected short‐wave UV (RUVIS) (96 in total), showing a distinct advantage to the CA and RUVIS imaging over the other two techniques with a 75% success rate in the dark and high background regions, due to its physical principle which neutralizes high background interference. The images were then scanned by the automatic fingerprint identification system (AFIS) to test its ability to correctly differentiate false background features from real ones, again, showing a superiority of the RUVIS with 63% of the total initial marked features, being real. Overall, the CA and RUVIS sequence was found to be an ultimate method for multiple, same‐type surfaces, with the RUVIS capable of visualization and capturing of the images simultaneously, significantly reducing the time of development and image processing.

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Sequential process – The introduction of CA in sequential processes was detailed in other sections of this report: added value of WPS applied in sequence with [CA ➭ BY40] [ 253 ] – See Section 4.3.6 ; determination of the most-suited techniques to be applied on different kinds of adhesives and tapes [ 254 ] – See Section 4.4.1 ; confirmation that the adhesive side of tapes must be protected when processing the non-adhesive side with [CA ➭ R6G] [ 255 ] – See Section 4.4.1 ; determination of the best protocols to detect fingermarks on polymer banknotes [ 256 , 257 ] – See Section 4.4.2 ; performance of the sequential processing involving LCA and VMD on thermal papers [ 258 ] – See Section 4.4.5 ; impact of CA on the efficiency of protein stains applied subsequently [ 259 ] – See Section 4.5.1 .…”

“…Three studies aimed at proposing the best protocol to detect fingermarks on banknotes: NIS 100 and NIS 200 [ 256 ], £5 and £10 Clydesdale Bank and Royal Bank of Scotland [ 257 ], and RMB [ 224 ]. The most relevant observations/conclusions of these studies were the following: on NIS 100 and NIS 200 polymer banknotes, [CA ➭ RUVIS@254 nm] was determined to be the most-suited detection sequence [ 256 ]. The other detection techniques that were considered in this study were VMD Au/Zn and black magnetic powder.…”

“…on NIS 100 and NIS 200 polymer banknotes, [CA ➭ RUVIS@254 nm] was determined to be the most-suited detection sequence [ 256 ]. The other detection techniques that were considered in this study were VMD Au/Zn and black magnetic powder.…”

Degradation of polymer banknotes through handling, and effect on fingermark visualisation

“…Various techniques, including vacuum metal deposition (VMD), cyanoacrylate fuming (CAF), powders and powder suspensions, have been found to work with differing degrees of success on several polymer banknotes [14][15][16][17][18][19][20].…”

A pseudo-operational trial: An investigation into the use of longwave reflected UV imaging of cyanoacrylate developed fingermarks

“…The use of UV imaging has long been documented as potential and operational imaging techniques for the visualisation of fingermarks, injuries, bite marks and bruises [10][11][12][13][14][15]. All wavelengths of UV (UV-C 100-280 nm; UV-B 280 -315 nm; UV-A 315-400 nm) can cause damage to the skin and eyes.…”