Contextual analysis strategy leads to rise in conviction rate for sexual assault cases

Sexual assault cases typically involve intense physical contact between victim and perpetrator, resulting in a high chance of trace transfer. In addition the victim's, and sometimes the suspect's, declaration is available, and can help direct the forensic investigation. However, many cases are still closed because of insufficient proof or an unknown perpetrator.Previously in Belgium, the forensic analysis strategy was often limited to the detection of human sperm fluid and if not found, the forensic part of the case was closed.Therefore, the Forensic Advice service from the Belgian National Institute for Criminalistics and Criminology (NICC) together with the public prosecutor's office of the Judicial district Antwerp, department Antwerp started "Project code 37". In Belgium every type of crime receives a code and sexual assault cases are categorized under code 37. Because a forensic advisor focuses on the potential of forensic examination on physical objects, the project focused on cases with samples taken on the victim or clothing available.The goal of the project was to perform a contextual analysis in order to go beyond the standard sperm fluid-orientated approach and evaluate if this had a positive impact on the conviction rate. The project also aimed to evaluate the impact of the consistent use of toxicological analyses on conviction rates. Through this systematic contextual analysis, it became clear that four clear categories could be defined: (1) cases with an unknown perpetrator, (2) cases where the suspect denies all contact, (3) cases where the suspect denies (part of) the sexual contact, and (4) cases where only the consent of the victim is disputed. These categories all assumed one female victim and one male perpetrator. Together with the NICC's DNA, trace evidence and toxicology lab, an analysis strategy was drafted for the four categories. All cases that do not fit this description were gathered in a fifth category (custom-made cases), as the victim's/perpetrator's sex has a significant effect on the forensic analysis strategy. At the end of the project, a comparison was made with the same set of cases from another judicial year where the standard analysis strategy was used. For all the categories for which data was available, there was a rise of the conviction rate and a decrease in the number of dismissed cases.