At this moment many surveillance systems are installed in public domains to control the safety of people and properties. They are constantly watched by human operators who are easily overloaded. To support the human operators, a surveillance system model is designed that detects suspicious behaviour in a non-public area. Its task is to alert the operators about suspicious events to give them the chance to investigate and take action. A prototype application has been implemented using stateof-the-art techniques from Computer Vision and Artificial Intelligence. Copyright © 2012 ACM.