As one of the key figures in ISIS today is ethnic Chechen, then it is important to track it back to where the roots of ISIS are.
So here is an interview with Gordan Hahn, author of Russia’s Islamic Threat and an analyst for the Geostrategic Forecasting Corporation:
http://www.npr.org/2014/09/05/345997449/hundreds-of-chechens-join-isis-including-group-s-no-2-leader