Fingerprints are used universally in the United Kingdom within criminal investigations. This comparative study researched the effectiveness of two fingerprint developing techniques, on an aluminium substrate in simulated fire crime scene conditions. Recent news articles
identified a direct link between alcohol and arson. The author identified scant literature regarding aluminium cans being researched as a material for fingerprint deposits in relation to arson crime scenes. The importance of this research is to highlight the significance of
fingerprint recovery within arson crimes but also to refute the notion that fire destroys all fingerprint evidence. Literature available on this subject widely investigated the effect of temperature on the survivability of fingerprints within fire dynamics such as the flashover stage.
In this study, fingerprints were deposited on aluminium can strips and then placed in a furnace. The strips were subjected to elevated temperatures with a range of 200°-500° for 30 minutes simulating the flashover stage, and then developed by powder lifting or cyanoacrylate fuming. Aluminium powder was used with a fibreglass brush to lift the prints and Sudan black 3 dye was applied to the cyanoacrylate prints for further enhancement. Each of the prints were then graded used the Home Office grading system and statistically
analysed using the Mann Whitney test.
This study demonstrated that elevated temperatures denature the fingerprints due to the evaporation of moisture within the print, giving the techniques limited ability. The temperature range was then narrowed down to 100°-300° where there was still a negative correlation between temperature and the grading of the prints. Cyanoacrylate fuming tended to give higher graded prints however due to the volume of data the techniques were found not to be significantly different. This research failed to reject the null hypothesis.
This study showed that higher temperatures demonstrating the flashover stage massively affected the techniques abilities to recover a viable print. Cyanoacrylate fuming had better results when used at lower temperatures however it did recover a print at 500° giving evidence of a fingerprint present. Powder lifting displayed better results at the narrowed range however cyanoacrylate fuming was a more sensitive technique. The two techniques were not statistically different, when undertaking further work the temperatures should be narrowed with more repeats to show the techniques abilities.
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