In this study the authors examined a criminal youth gang of 35 persons in the Netherlands, using social network analysis, to answer the following questions. To what extent is it possible by means of police records to estimate the size of the complete social network of this criminal youth gang? To what extent are members of this original group part of the core of the complete network? To what extent have members of the original group a central position in the complete network (key players) and are, as such, responsible for holding the complete network together? Information is derived from police records. Results show that the size of the total network of this criminal youth gang consists of 593 individuals with a core of around hundred persons. Seven persons were identified as key players, among which six persons belonged to the original group. The social network approach in this study provides police and justice important indications for a more tailored approach regarding individuals within criminal networks.