ISIS executing disillusioned foreign jihadists.

"Morale among the fighters was affected by the group’s shift toward governing areas it controls and because of U.S.-led air strikes halting their advances in Syria and Iraq.

“Local fighters are frustrated – they feel they’re doing most of the work and the dying?…?foreign fighters who thought they were on an adventure are now exhausted,” the opposition activist told the daily."

http://english.alarabiya.net/en/News/middle-east/2014/12/20/ISIS-executes-100-deserters-in-Syria-s-Raqqa-report.html