Tracing crime Illuminating biochemical properties of biological traces

The aim of this thesis is to develop and advance forensic science methodologies for use in forensic investigations, to acquire additional information from biological traces based on their biochemical properties. As such, a fluorescent-based technique was developed to address these needs, next to investigating the integration of immunolabeling with conventional forensic techniques. The research focused on several key areas, including: understanding the role of oxidation in aging body fluids (Chapter 2), identifying specific fluorescent signatures for body fluid identification (Chapter 3), and analyzing the fluorescent properties of vaginal fluid (Chapter 4). In addition, in Chapter 5, a method for estimating the age of semen stains based on protein-lipid oxidation was introduced, which was further developed into a portable fluorimeter for on-site application (Chapter 6). Chapter 7 focused more on the temporal changes in fluorescent compounds in semen stains. Further research was focused on assessing the compatibility of immunolabeling with DNA analysis and vacuum metal deposition for fingermark analysis (Chapters 8 and 9). In conclusion, this thesis provides valuable insights into the biochemical properties of biological traces, highlighting the potential of fluorescence-based methods for detecting, identifying, and estimating their age. Furthermore, the research also provides direction for the use of immunolabeling in combination with important conventional techniques in forensic case work.