{"p"=>"This study delves into the dynamics of collaboration within networks of professional money launderers known to the police in the Netherlands. Building on prior research, which revealed that financial facilitators aiding drug trafficking organizations can be linked in extensive collaborative networks, this study explores the factors influencing the formation of these ties. Using Dutch police registration data on 117 financial facilitators and applying Exponential Random Graph Models (ERGMs), the research identifies key personal and relational attributes and features of the overall collaboration network that explain tie formation. The findings reveal that financial facilitators who operate more business-like have a higher probability to form connections with other financial facilitators. Additionally, underground bankers seem to be more inclined to collaborate with other underground bankers in the Netherlands than with other types of financial facilitators. The study further suggests a trend toward the formation of triadic relationships over dyadic ones within these observed money laundering networks."}