Evaluating The Viability Of Obtaining Dna Profiles From Dna Encapsulated Within The Layers Of Counterfeit Banknotes

The use of digital printing has made the linking of counterfeit banknotes from the same organised crime groups difficult for law enforcement agencies and Central Banks. A more reliable and objective means of attributing counterfeits to a common source is therefore required. An area of potential forensic evidence could be from the acquisition of trace DNA encapsulated between the layers in a multilayer counterfeit or from the adhesive used for adhesive external features such as foil patches or foil strips. By establishing a novel method for the removal and extraction of DNA, the possibility of profiling encapsulated DNA from counterfeit euro banknotes could be evaluated.

Preliminary research established that DNA could be removed from the adhesive side of dot matrix holograms using Chelex resin and phenol chloroform extraction. However, the percentage yield of DNA successfully extracted was low, with most results being below 20%. To increase the release of DNA from the adhesive layer of the dot matrix holograms, xylene, a 1,2-indandione working solution and ethanol were shown to be successful at separating the adhesive layers of two-layer counterfeits and on the adhesive used on dot matrix holograms present on some counterfeit banknotes. Xylene was applied in the swabbing of dot matrix holograms in a simulated procedural study involving the extraction of DNA through three extraction processes. Samples were then quantified and DNA profiled to establish the condition of present touch DNA. Both Chelex resin and phenol chloroform gave partial DNA profiles in the majority of samples, counter to what the qPCR data suggested in prior analysis.

A modified Chelex resin extraction with ethanol-based swabbing was applied to seized counterfeit banknotes to show the potential of the methodology established. However, no profiles were successfully acquired from either the dot matrix holograms or the imitation metallic threads analysed. To account for a potential loss of DNA, direct PCR was carried out on segments of imitation metallic thread taken from 24 counterfeit banknotes. Two of the samples gave partial DNA profiles that had alleles that could be used for RMP analysis and one profile where the allelic peaks were challenging to interpret. Although no link between the DNA profiles could be established using profile comparisons, the results do highlight the potential of acquiring DNA profiles from DNA encapsulated in the layers of counterfeit banknotes.

This research shows the capability of acquiring DNA from counterfeit banknotes for forensic investigations, which with further research could be part of a standard procedure for counterfeit banknote processing to gain intel on organised crime groups.