The availability of vast amount of closed-circuit television (CCTV) videos and the critical need for a fast and accurate analysis of all its content especially in security applications, has led to an equally urgent need for its automated processing. Indeed, identifying suspected acts of vandalism or crime from a massive collection of videos are extremely tedious using manual approach. Therefore, with application for security in mind, this paper presents a new approach for automated analysis of CCTV using ontology-based knowledge representation and reasoning. The proposed approach exploits event semantics for the identification of possible crime and perpetrators. The framework consists of salient feature extraction from CCTV footage, inter-level data parsing, highlevel conceptual model event representation, rules inferencing, knowledge reasoning and queries. Although a complete (endto-end) framework was implemented, the main contribution of this work is primarily on the high-level analysis and proposed underpinning Ontology. The proposed approach has been validated with a very large database of CCTV footage from the 2011 London riots. The results validate the strength of the approach.