The link between crime and terrorism dates back decades. Among the theories on the relationship between the two phenomena, the works of Alex P. Schmid, the theory of Crime-Terror Continuum of Tamara Makarenko, and the “terror-crime interaction spectrum” model of Louise I. Shelley and John T. Picarelli provide the basis for the theoretical approach.
The study also addresses the issue of terrorism financing by criminal methods. The financing of European terrorists is different from the financing of terrorists in the Middle East. The income of crime allows self-sufficiency, so financial support from a terrorist organization is often not even needed. In addition, jihadist terrorists in many cases choose methods, such as stabbing or ramming, that does not require much expense. Jihadist extremists are mostly involved in not organized crime, and there are indications that extremists fund their activities in part from such petty crimes.
The study also addresses the framework of the relationship between criminals and terrorists, such as recruitment, networking and knowledge transfer. One of the points of contact between criminals and jihadists is the prison, which carries dangers such as the radicalization of criminals or the criminal training of religious extremists. Finally, several terrorists with a criminal history - who carried out terrorist attacks on the territory of the European Union - are also presented.