Methods for obtain identifiers, such as International Mobile Subscriber Identities (IMSIs) and International Mobile Station Equipment Identities (IMEIs), of mobile communication terminals, and associate these identifiers with other items of identifying information provided by users of the terminals. A local interrogation device may be installed that imitates a legitimate base station belonging to a cellular network, at a control checkpoint. Local interrogation devices are connected to a global interrogation device in a hierarchical network, whereby the local interrogation devices are assigned a priority that is higher than that of the global interrogation device. The global interrogation device provides cellular coverage to a larger area that contains the control checkpoints, while the local interrogation devices provide more localized cellular coverage to the control checkpoints.