# A Bayesian Hierarchical Model for Criminal Investigations

## TL;DR

This paper introduces a Bayesian hierarchical model to assess threats in criminal investigations by integrating real-time evidence and expert judgments, demonstrated through a hypothetical terrorist attack scenario.

## Contribution

It presents a novel three-level Bayesian hierarchical framework tailored for criminal threat assessment, enabling dynamic evidence integration and expert calibration.

## Key findings

- Model effectively propagates routine and unexpected evidence.
- Framework adapts to domain expert judgments.
- Illustrative example demonstrates practical application.

## Abstract

Potential violent criminals will often need to go through a sequence of preparatory steps before they can execute their plans. During this escalation process police have the opportunity to evaluate the threat posed by such people through what they know, observe and learn from intelligence reports about their activities. In this paper we customise a three-level Bayesian hierarchical model to describe this process. This is able to propagate both routine and unexpected evidence in real time. We discuss how to set up such a model so that it calibrates to domain expert judgments. The model illustrations include a hypothetical example based on a potential vehicle based terrorist attack.