Secondary and tertiary transfer of latent fingermarks using a sticky note - A feasibility study

Latent fingermarks are enhanced in order to be visible and available for comparison to determine source. Once a fingermark has been identified to a source, the activity that led to it being left on a particular surface may need to be determined. It has been previously shown that under certain conditions fingermarks initially deposited onto a surface (the primary transfer) can be transferred on to another substrate through direct contact - secondary transfer. This study investigates the possibility of secondary and subsequent tertiary transfer using sticky notes. To explore secondary transfer, fingermarks were deposited directly onto two different brands of sticky notes, spanning the adhesive and non-adhesive areas, and then placed in direct contact with paper for up to 72 h under a 5 kg weight. For some donors, there was transfer of fingermarks from the sticky note to the paper, with better results for the adhesive areas. The quality of the transferred fingermarks was dependent on initial fingermark quality and the transferred fingermark was a mirror image of the original. The type of paper used as the secondary substrate was also shown to have an effect. Given the adhesive nature of sticky notes tertiary transfer was also investigated and the potential to lift fingermarks from a glass slide and transfer them onto paper or a second glass slide. In the case of transfer to paper, there were only tertiary transferred fingermarks considered to be of useful quality (score 3 or 4) in 6% of samples and a further 33% of samples were detected but provided evidence of contact only (score 1 or 2) (n = 120). For transfer to glass, tertiary transferred samples were of poorer quality with no useful fingermarks and only 3% of samples scoring 1 or 2 (n = 120). The latter was in part due to the deposition of sticky note adhesive traces obscuring the fingermarks. In the case of tertiary transfer, fingermarks on the final tertiary surface were in the correct orientation. This work demonstrates that whilst tertiary transfer of fingermarks is possible under the laboratory conditions used, the likelihood of the effective transfer of a useful and potentially identifiable fingermark is in reality low.