Militant groups such as the Islamic State (IS) can offer direction and a certain meaning in life that some people crave, said Professor Andrew Silke from the University of East London, where he is programme director for Terrorism Studies. Prof Silke, who serves as a counterterrorism consultant to government agencies in Britain and America, is in Singapore to give a lecture at the S. Rajaratnam School of International Studies. In this interview with TODAY, he examines the appeal of IS and suggests ways to deal with returning fighters.