Despite major implications for forensic casework, limited research has been done on investigating secondary transfer of latent fingermarks. Adhesive tapes, such as duct tape, can potentially lift latent fingermarks from other surfaces due to their adhesive properties. This study aimed to investigate the possible secondary transfer between layers of adhesive tape and tape and other substrates (metal and plastic). Fingermarks were directly placed onto a primary substrate and subsequently brought into contact with a secondary substrate for varying duration. After visualization, the quality of the fingermarks was assessed to measure their loss and transfer. It was shown that fresh latent fingermarks can transfer between layers of adhesive tape, with instances of sufficient quality for comparison of the transferred fingermarks. In contrast, no transfer was detected after one week. However, a substantial loss of quality of the initially deposited fingermark was observed, suggesting an influence of time. Overall, it was shown that secondary transfer is possible and that caution has to be taken when analysing and interpreting latent fingermarks on adhesive tapes.
Adhesive tape is a common piece of evidence that can contain a myriad of traces. Due to its adhesive properties, adhesive tape can potentially collect traces unrelated to the crime or relocate crime-relevant traces. This secondary transfer of traces can have crucial implications for the evaluation at the activity level. Therefore, this study investigated the secondary transfer of DNA between layers of adhesive tape and tape and other case- and laboratory-relevant substrates. A drop of diluted blood was deposited on different primary substrates (i.e. duct tape, metal, plastic, textile, nitrile gloves). Subsequently, the primary substrate was brought into contact with a secondary substrate, and DNA was collected from both surfaces to measure transfer rates. The highest transfer rates were detected between the adhesive side of the tape and plastic, whereas the lowest transfer rates were detected between the adhesive side and textile. It was shown that the adhesive readily collects DNA from plastic and nitrile gloves commonly used in the laboratory, which highlights the importance of working with DNA-free materials. Therefore, this study demonstrated the need for caution when interpreting traces on adhesive tapes, always taking possible situations of secondary transfer into account.
