Evaluative approach to semen transfer in a case of alleged sexual assault: A case study.

• Here we demonstrate the evaluation of forensic evidence using a real life case of an alleged sexual assault. • We have used the European Network of Forensic Science Institutes (ENFSI) guideline for evaluative reporting in forensic science. • We show evaluation is possible even when additional information is provided and some or all results are known. This paper demonstrates a logical framework for evaluating forensic evidence, first described by Cook et al. [1,2], using a casework example of an alleged sexual assault involving semen transfer. Here we show in real time how the case strategy can change with additional information and how to use available experience and published data to interpret the findings obtained, given the background information provided. The findings of the case are interpreted using the Bayesian approach and are reported by giving the strength of support of scientific findings for one proposition rather than a competing proposition, as per the European Network of Forensic Science Institutes (ENSFI) guideline for evaluative reporting. We believe that using this paper as a template will aid other Forensic Science Practitioners (FSP) to add value and weight to their work by assisting them in evaluating and interpreting their own findings. [ABSTRACT FROM AUTHOR]