Non-invasive, rapid, on-site detection and identification of body fluids is highly desired in forensic investigations. The use of fluorescence-based methods for body fluid identification, have so far remain relatively unexplored. As such, the fluorescent properties of semen, serum, urine, saliva and fingermarks over time were investigated, by means of fluorescence spectroscopy, to identify specific fluorescent signatures for body fluid identification. The samples were excited at 81 different excitation wavelengths ranging from 200 to 600 nm and for each excitation wavelength the emission was recorded between 220 and 700 nm. Subsequently, the total emitted fluorescence intensities of specific fluorescent signatures in the UV–visible range were summed and principal component analysis was performed to cluster the body fluids. Three combinations of four principal components allowed specific clustering of the body fluids, except for fingermarks. Blind testing showed that 71.4% of the unknown samples could be correctly identified. This pilot study shows that the fluorescent behavior of ageing body fluids can be used as a new non-invasive tool for body fluid identification, which can improve the current guidelines for the detection of body fluids in forensic practice and provide the robustness of methods that rely on fluorescence.
MULTIFILE
fingerprints are a commonly exploited type of evidence and can be crucial in a criminal investigation. The process of individualization or exclusion of a donor relies on the comparison of ridge detail characteristics between a fingermark, found at a crime scene, and reference fingerprints, collected under controlled conditions (either or not stored in a database). Although this process has been successfully used for over a century, fingermarks found at a crime scene are of limited value for a criminal trial if the corresponding reference fingerprint is not available, or the found fingermark is of poor quality. Fingerprints consist of donor secretion, mainly eccrine and sebaceous, of which the exact composition is likely influenced by many (both endogenous and exogenous) factors, including donor traits, habits and activities. Analysis of the chemical composition could thus potentially lead to the retrieval of donor information from those fingerprints that yielded no information in the traditional comparison process. The main aim of this dissertation was to determine what donor information can reliably and validly be derived from the chemical analysis of the fingerprint composition, in order to be used in forensic investigations...
