Preliminary investigations into the use of single metal deposition II (SMD II) to visualise latent fingermarks on polyethylene ‘zip-lock’ bags in Western Australia

This study explores the performance of the gold nanoparticle based single metal deposition II (SMD II) technique in developing fingermarks on selected polyethylene surfaces under different environmental conditions in a Western Australian context. Latent fingermarks collected on calcium carbonate/polyethylene blend paper and polyethylene ‘zip-lock’ bags were stored in dry and wet environments for up to 30 days. Useful marks were consistently developed after storage in dry conditions; however, the proportion of useful marks decreased after submersion in water for 30 days. Additionally, background staining on the zip-lock bags had a large impact on the performance of the technique. SMD II was subsequently compared to dry powdering using Lightning Black powder for the detection of latent fingermarks on polyethylene zip-lock bags left in indoor and outdoor environments for up to 4 weeks. SMD II outperformed dry powdering in both environments, showing its potential as a detection technique for latent fingermarks on polyethylene surfaces exposed to environmental conditions.