Development and pilot testing of a prototype cyanoacrylate chamber for in-field fingermark detection and enhancement

Abstract

Fingermarks found on moveable objects at crime scenes are usually sent back to a laboratory for further detection and enhancement. One fingermark enhancement technique that is conducted under standard laboratory conditions is cyanoacrylate (CA) fuming. CA fuming is a non-porous fingermark enhancement technique, which involves exposing an object to superglue vapours in an enclosed chamber (Suboch, 2016). Recent advancements in technology have allowed policing agencies to conduct CA fuming at crime scenes using a range of approaches. The current approaches to in-field CA fuming have advantages but also clear disadvantages that limit their incorporation into routine casework. In this project, a prototype portable chamber has been developed to address some of the current limitations to in-field CA fuming, which include limited portability and thus accessibility to crime scenes and poor fingermark development due to unfavourable environmental conditions. This project examined the capabilities of the portable chamber to produce consistent fingermark development through the circulation tests that were conducted. Additionally, the ability of the portable chamber to fume fingermarks under a range of ambient conditions was also examined while also comparing the performance of the portable chamber to a standard laboratory chamber. Back-to-back fuming cycles were conducted to test the reproducibility of the portable chamber. These tests also highlighted that variable relative humidity (RH) and variations in donor secretions were the biggest factors in determining the quality of fingermark development. This project found that when RH is 80% or higher, fingermark development was maximised, for all donor strengths. When RH was low, a reduction in the quality of fingermark development was observed. When the performance of the portable chamber was compared to a standard laboratory chamber, the results demonstrated that for 50% of fumed fingermarks, there was no difference in development between the portable chamber and the standard laboratory chamber. The other 50% of fingermarks had slightly greater fingermark development occurring in the standard laboratory chamber. Through the development and testing of the portable chamber, this project has addressed some of the current limitations to in-field CA fuming. The results of this project indicate that a portable chamber can produce reproducible results, but the quality of fingermark development is dependent on the RH of the chamber. Due to a limited sample size for all tests, future work should be conducted to optimise the chamber design in order to further increase the reproducibility of the prototype chamber and quality of fumed fingermarks.

Date of Thesis submission	2022
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Brenden Riley (Supervisor), Robert Ebeyan (Supervisor), Val Spikmans (Supervisor) & Chris Lennard (Supervisor)