Adhesive tape is a common item which can be encountered in criminal cases involving rape, murder, kidnapping and explosives.
It is often the case that a suspect deposits latent fingerprints on the sticky side of adhesive tape when tying up victims, manufacturing improvised explosive devices or packaging illegal goods. The problem that is often encountered though is that the adhesive tape found at crime scenes or on forensic exhibits are usually stuck together or attached to a certain substrate, thus rending any latent fingerprints be hidden beneath the tape.
Current methods to detect latent fingerprints hidden beneath the adhesive layer, require it first to be peeled off and then the application of some form of physical or chemical method to develop the fingerprints on either side of the tape (adhesive / non-adhesive).
Optical coherence tomography (OCT) is a novel application technique in forensics which allows for the taking of non-invasive, high resolution, cross-sectional, structural images.
In a study conducted by Chinese researchers, a custom-built spectral-domain OCT (SD-OCT) system with a hand-held probe was employed to detect fingerprints hidden beneath different types of adhesive tapes.
Three-dimensional (3D) OCT reconstructions were performed and images were captured to reveal the hidden fingerprints.
This experiment demonstrated that OCT can allow for the detection and recovery of latent fingerprint hidden between two pieces of non-transparent adhesive tapes in situ and in a fast manner, while eliminating the need of peeling them off.
It also demonstrates that OCT is a promising tool for rapidly detecting and recovering high quality images of latent fingerprints hidden beneath adhesive tape without any changes to the original state and preserve the integrity of the evidence.
To learn more about OCT and further results from the study,
Read the Paper Here