Identifying roles in drug trafficking using geolocation from telephone data collected during investigations
Communication surveillance, one of the main tools used in investigations of drug trafficking, is used to reconstruct criminal activity, identify the offenders, determine their respective roles within the trafficking operation, and eventually locate them. Research into the use of telephone data to study criminal groups currently relies mainly on transcripts of phone conversations obtained through police wiretapping. Our exploratory research also benefited from privileged access to telephone data from wiretaps and records of call details collected both in real time and retrospectively during investigations. Our research focuses on the relation between the roles of individuals involved in drug trafficking and the spatial patterns detected in telephone communications. We asked whether the role of a protagonist – his/her function and place within a trafficking group – can be inferred from telephone activities and addressed this question through a spatiotemporal analysis of call detail records and wiretaps from 20 individuals implicated in drug trafficking. The selected individuals could be classified into three different roles : dealer, mid-level or high-level wholesaler, and cross-border or national courier. To determine their mobility, median locations, convex-hull areas, and the average distance travelled per day were calculated for each individual and by role type. The results support the hypothesis that individual roles influence the patterns found in telephone data. Couriers can be differentiated from dealers and wholesalers based on identifiable geographic patterns. Dealers can also be distinguished from wholesalers. These results confirm the proposed approach and reveal the potential of the analysis of telephone data to infer roles in drug trafficking.