Social Network Analysis for Crime Analysts
Preface
In 2011, law enforcement agencies in the United States faced mounting pressure to dismantle a sprawling drug trafficking operation that spanned multiple cities and involved various criminal subgroups. Traditional investigative methods, such as surveillance and wiretaps, had led to dozens of arrests, but the core leadership of the network remained insulated and elusive. With the organization’s adaptability and ability to replace arrested members, authorities struggled to make meaningful headway. This criminal enterprise, structured in decentralized cells, continued to thrive by exploiting its hidden communication channels and relying on intermediaries to shield the leaders from direct exposure.
Recognizing the limitations of conventional approaches, investigators turned to social network analysis (SNA) to map out the complex web of relationships within the organization. Using SNA, they were able to identify not just the individuals who were visible through direct criminal activities but also those who occupied critical structural positions within the network. SNA revealed that a handful of individuals, who had previously appeared minor in traditional investigations, were in fact brokers who facilitated communication between isolated cells and the core leadership. These brokers operated at the intersection of different subgroups, acting as the glue that held the organization together (Morselli 2009). By strategically targeting these brokers, law enforcement disrupted key communication pathways and destabilized the network. The arrest of these intermediaries created confusion within the organization and led to further information leaks, ultimately exposing the previously hidden leadership structure. Authorities were able to make high-profile arrests, effectively crippling the operation (Malm and Bichler 2011).
This case exemplified the power of SNA to reveal otherwise invisible roles and relationships within criminal organizations, offering law enforcement a data-driven approach to strategically dismantling large-scale criminal enterprises. In today’s increasingly interconnected world, the study of social networks has become an essential tool for understanding crime. Why? Crime does not happen in isolation. Individuals involved in criminal activities are often embedded within broader social networks that can influence and even facilitate their behaviors. By understanding these networks, crime analysts can uncover hidden relationships between individuals, identify key players, and predict the movement of illicit information or resources. SNA encompasses a powerful set of tools (both theoretical and analytical) that help analysts move beyond simply tracking individual offenders to mapping the structures that support criminal behavior. This shift from a focus on individual actors to the entire system allows for a more nuanced understanding of how crime operates in communities and institutions, facilitates positive impacts on criminal apprehension, crime reduction, and long-term prevention efforts.
But SNA is not limited to analysts working within a law enforcement context. On the contrary, SNA has applicability to multiple problems faced across a variety of criminal justice agencies:
Prisons: Inside prisons, social networks influence everything from inmate behavior to contraband smuggling and gang activity. SNA helps identify inmate leaders, those at risk of victimization, and potential sources of conflict. Understanding these dynamics can improve safety and reduce violence.
Probation and Parole Officers: SNA can help officers understand the social networks of individuals on supervision, which may include influences that either support or undermine rehabilitation. By identifying pro-social networks, officers can encourage engagement with positive social influences, while also identifying risk factors related to recidivism, such as association with former criminal peers.
Prosecutors Defense Attorneys, and Judges: SNA can be used in building cases, particularly in conspiracy or organized crime prosecutions. It helps prosecutors demonstrate the relationships and communication patterns between co-conspirators, providing clearer evidence of a criminal enterprise or joint activity. For defense attorneys, SNA can be used to identify alternative explanations for their client’s involvement in a criminal network or to challenge the prosecution’s portrayal of their client’s role. If the client is not a central figure in the network, this could be used to argue for lesser charges or reduced sentences. Finally, judges can use SNA to help understand a defendant’s social network and can provide insights into the likelihood of recidivism or flight risk.
Policy Makers and Criminal Justice Reform Advocates: Policy makers can use SNA to understand the broader social dynamics that contribute to crime, such as how poverty, unemployment, and social exclusion fuel criminal networks. This can guide the development of crime prevention policies that target root causes and dismantle harmful networks, while promoting pro-social ones.
The Social Network Analysis for Crime Analysts (SNACA) textbook introduces the foundational concepts and techniques of social network analysis, providing a comprehensive framework for crime analysts to apply in their day-to-day work. Whether you are currently working in a criminal justice agency, or plan to do so in the future, the content of this textbook will prepare you to excel in such a role through the application of SNA. You will learn to map out criminal networks and analyze the roles of individuals within them. Through this lens, you will gain the ability to assess which individuals or nodes in a network are most critical to disrupting criminal activities. Moreover, these techniques will allow you to develop targeted strategies for crime and disorder reduction. By focusing on the most influential players within criminal networks, you can maximize the effectiveness of apprehension efforts, creating tangible outcomes that can dismantle harmful networks and reduce violence or other forms of crime in the community.
Beyond tactical benefits, social network analysis empowers crime analysts to adopt a more preventive approach. By identifying patterns of association and influence within a network, you will be equipped to contribute to crime prevention strategies before criminal behavior escalates. For instance, by identifying vulnerable individuals on the periphery of a network, you can help law enforcement intervene early to redirect them away from criminal pathways. Additionally, the evaluation skills you gain will help you measure the effectiveness of these interventions, ensuring that existing strategies evolve to meet the unique challenges of crime and disorder. By the end, you will be well-prepared to make a meaningful contribution to criminal apprehension, crime and disorder reduction, prevention strategies, and the ongoing evaluation of those efforts.
This textbook is designed to introduce you to basic concepts used in SNA. The textbook is divided into chapters that cover a variety of these concepts. At the end of each chapter is a “Test your Knowledge” section that includes questions to determine whether you feel comfortable discussing the material. I would encourage you to think through these prompts after you read the chapter, but also come back to them occasionally to refresh your memory. The textbook is not exhaustive, but most of the major topics are discussed.
For those readers who are new to SNA, I would suggest starting at the beginning and working through in chronological order. For those readers who are already familiar with SNA, feel free to skip through the chapters.