Entropy and Network Centralities as Intelligent Tools for the Investigation of Terrorist Organizations

Abstract

In recent years, law enforcement authorities have increasingly used mathematical tools to support criminal investigations, such as those related to terrorism. In this work, two relevant questions are discussed: “How can the different roles of members of a terrorist organization be recognized?” and “are there early signs of impending terrorist acts?” These questions are addressed using the tools of entropy and network theory, more specifically centralities (degree, betweenness, clustering) and their entropies. These tools were applied to data (physical contacts) of four real terrorist networks from different countries. The different roles of the members are clearly recognized from the values of the selected centralities. An early sign of impending terrorist acts is the evolutionary pattern of the values of the entropies of the selected centralities. These results have been confirmed in all four terrorist networks. The conclusion is expected to be useful to law enforcement authorities to identify the roles of the members of terrorist organizations as the members with high centrality and to anticipate when a terrorist attack is imminent, by observing the evolution of the entropies of the centralities.

Directed Criminal Networks: Temporal Analysis and Disruption

“…The global efficiency is also increasing at month 12, but not as sharply, given the precaution that communication is governed by intermediaries. In this sense, previous findings relating sharp changes in global network indicators with periods of intense activity of illicit organizations are confirmed [54,55]. A notable difference between the in and out degree entropies is also observed: the in-degree entropy reaches a global minimum at month 12, while the out-degree entropy reaches a global maximum.…”

“…Monitoring the temporal evolution of the selected network indices in time may provide law enforcement authorities with data-oriented intelligence that can complement empirical evidence and expert opinion. This is demonstrated by the observed sharp increase in certain network indices during the monitoring period (Section 3.2), a finding that can be proved useful for alerting the authorities to increasing criminal activity [54,55].…”

Interoperability and Targeted Attacks on Terrorist Organizations Using Intelligent Tools from Network Science

“…We examine several attack strategies for sequentially removing nodes, based on different centrality criteria, reflecting distinct social roles in terrorist networks [48]:…”

“…By mapping physical contacts within four real-world terrorist networks, the research uncovers distinctive roles linked to specific centrality values, and intriguingly, the imminent threat of an attack correlates with the evolutionary pattern of these centralities' entropies. This illuminates an invaluable tool for law enforcement, empowering them to not only identify pivotal figures within terrorist cells but also predict an imminent attack through monitoring the evolution of the centralities' entropies [48]. In a parallel vein, the second paper champions an innovative, quantitative, and unbiased methodology based on network theory to explore the distinct roles within terrorist organizations.…”

“…In counterterrorism and law enforcement, our team contributed two groundbreaking papers. "Entropy and Network Centralities as Intelligent Tools for the Investigation of Terrorist Organizations" [48] and "Investigation of Terrorist Organizations Using Intelligent Tools: A Dynamic Network Analysis with Weighted Links" [49] both leverage mathematical tools to unlock the obscured behaviors and structure of terrorist organizations. The first paper utilizes entropy and network theory to discern the diverse roles within a terrorist organization and detect early signs of impending attacks.…”