A multiplex network perspective on illicit firearms trafficking

Illicit firearms trafficking is a transnational problem affecting communities worldwide. It enables, and is frequently intertwined with, other organized crime activities, such as drug and human trafficking. Illicit firearms trafficking is considered to be primarily carried out by organized criminal groups. A way to map and measure relationships and flows between individuals in firearms trafficking groups is provided by social network analysis (SNA). This chapter focuses on using SNA to understand the criminal activities in firearms trafficking networks and the social structures facilitating those activities in the European context. By means of a multiplex network approach, six network layers or tie types were examined, including ties that support the flow of commodities (firearms, money, and equipment) and those that facilitate social dynamics (orders, negotiation, and planning). A case study of a Dutch firearms trafficking network that was subject to police investigation was used. The merged network consisted of forty-two actors with 224 ties between them, including ties of which the link type was unknown. SNA metrics (density, degree centralization, average degree, degree centrality, and betweenness centrality) were calculated for the merged network and the six individual network layers. Results are discussed in light of the literature on the social organization of criminal groups. The chapter concludes with implications of results for policy and practice.