Uncovering illicit supply networks and their interfaces to licit counterparts through graph-theoretic algorithms

Research output: Contribution to journalArticlepeer-review


The rapid market growth of different illicit trades in recent years can be attributed to their discreet, yet effective, supply chains. This article presents a graph-theoretic approach for investigating the composition of illicit supply networks using limited information. Two key steps constitute our strategy. The first is the construction of a broad network that comprises entities suspected of participating in the illicit supply chain. Two intriguing concepts are involved here: unification of alternate Bills-of-materials and identification of entities positioned at the interface of licit and illicit supply chain; logical graph representation and graph matching techniques are applied to achieve those objectives. In the second step, we search for a set of dissimilar supply chain structures that criminals might likely adopt. We provide an integer linear programming formulation as well as a graph-theoretic representation for this problem, the latter of which leads us to a new variant of Steiner Tree problem: Generalized Group Steiner Tree Problem. Additionally, a three-step algorithmic approach of extracting single (cheapest), multiple and dissimilar trees is proposed to solve the problem. We conclude this work with a semi-real case study on counterfeit footwear to illustrate the utility of our approach in uncovering illicit trades. We also present extensive numerical studies to demonstrate scalability of our algorithms.

Original languageEnglish (US)
Pages (from-to)224-240
Number of pages17
JournalIISE Transactions
Issue number3
StatePublished - 2024
Externally publishedYes


  • Illicit trade
  • Steiner tree problem
  • bill-of-materials
  • dissimilar trees
  • generalized group Steiner tree
  • illicit supply chains

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering


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