Some 5000 men, women and children have travelled from Europe to Syria and Iraq
since 2012. An estimated 1500 of these foreign terrorist fighters (FTF) have returned
so far. Some came back disillusioned, or traumatised by their war experiences, but
others returned with malicious intentions.
The first successful attack by a returnee in Europe occurred in 2014, with Mehdi
Nemmouche’s shooting at Brussels’ Jewish Museum. Several other attacks followed,
culminating with the coordinated attacks in Paris in November 2015 and Brussels in
March 2016. Since then, no new attack by returnees has occurred but that does not
mean the threat is over. Plots continue to be set up, mostly by so-called homegrown
terrorist fighters with limited means and skills, but with potentially dramatic results
should they succeed. They could pose a serious security challenge.
Studies of past jihadi waves show that veteran fighters can play a crucial role in
perpetuating the jihadi movement from one generation to another, often starting
from their prison cells, where many returnees from Syria and Iraq now serve their
sentences.