Representing and Evaluating Legal Narratives with Subscenarios in a Bayesian network

In legal cases, stories or scenarios can serve as the context for a crime when reasoning with evidence. In order to develop a scientifically founded technique for evidential reasoning, a method is required for the representation and evaluation of various scenarios in a case. In this paper the probabilistic technique of Bayesian networks is proposed as a method for modeling narrative, and it is shown how this can be used to capture a number of narrative properties. Bayesian networks quantify how the variables in a case interact. Recent research on Bayesian networks applied to legal cases includes the development of a list of legal idioms: recurring substructures in legal Bayesian networks. Scenarios are coherent presentations of a collection of states and events, and qualitative in nature. A method combining the quantitative, probabilistic approach with the narrative approach would strengthen the tools to represent and evaluate scenarios. In a previous paper, the development of a design method for modeling multiple scenarios in a Bayesian network was initiated. The design method includes two narrative idioms: the scenario idiom and the merged scenarios idiom. In this current paper, the method of Vlek, et al. (2013) is extended with a subscenario idiom and it is shown how the method can be used to represent characteristic features of narrative

Towards Sound Forensic Arguments: Structured Argumentation Applied to Digital Forensics Practice

Digital forensic practitioners are increasingly facing examinations which are both complex in nature and structure. Throughout this process, during the examination and analysis phases, the practitioner is constantly drawing logical inferences which will be reflected in the reporting of results. Therefore, it is important to expose how all the elements of an investigation fit together to allow review and scrutiny, and to support associated parties to understand the components within it. This paper proposes the use of ‘Structured Argumentation’ as a valuable and flexible ingredient of the practitioners’ thinking toolbox. It explores this approach using three case examples which allow discussion of the benefits and application of structured argumentation to real world contexts. We argue that, despite requiring a short learning curve, structured argumentation is a practical method which promotes accessibility of findings facilitating communication between technical and legal parties, peer review, logical reconstruction, jury interpretation, and error detection