Challenge and response system for identifying non-credentialed occupants and method

A system and method for determining authorization of individuals at a premises is disclosed. The system (e.g. security system) includes interrogator devices such as mobile computing devices that are carried through the premises by an interrogator. The interrogator devices send challenge beacons for triggering responses from target user devices carried by users. A management system then confirms whether users of the target user devices are authorized users based on the responses received by the interrogator devices. Examples of target user devices include mobile computing devices such as smart phones/tablet devices, and auxiliary devices such as smart badges and wallets. In embodiments, the interrogator can also carry an auxiliary device having an integrated camera system that captures image data of the users, where the management system additionally confirms whether the users are authorized by comparing the image data along with information in the responses to stored records of authorized users.