At the moment they follow a classical guerilla tactic, hit out of nowhere and disappear, and the culture of sacrifice makes it easier for the leaders to find willing idiots to blow themselves up (I wonder why none of the leaders ever puts himself or his familiy in harm´s way). At the moment it is almost impossible to single possible terrorists out, esp. since they operate decentralised and just loosely connected. There was an interesting article in German Spiegel magazine last week. They described 4 types of terrorists:
1) the islamist radical, who has been fighting in Afghanistan and is wanted in his home country, not active in his country of residence, because he is too well known to the authorities, except for propaganda and recruitment, where his status as a former fighter gives him special respect.
2) The radical sleeper, like the 9/11 terrorists, friendly college students from muslim countries, inconspicious, might even break religious rules, like drinking alcohol and having girlfriends, as a camouflage, often well educated and intelligent.
3) The rootless young second generation immigrant, his parents, hard working people, moved in from a poor muslim country. The son doesn´t feel accepted by the mainstream society, might turn to petty crime and gangsterism ort he might turn to radical religion to spite the non-muslim enviroment. If a former criminal, he might "see the light" while doing a prison term and be radicalised to make up for his former "evil" life. It looks as if several of the Madrid bombers belonged to this group.
4) Converted people from Western countries. Dissappointed with their lifes, they turn to a religion which will give them "clear rules and answers". Like many freshly converted people, they are extra radical and want to emphasise their break with their old lifes. Currently a converted German is sitting in a French jail for involvement in the bombing on a synagogue in Tunisia. Another young German got deported from Israel, where he was sitting in jail as a Hisbullah member after getting caught preparing a bombing. Hisbullah liked him because of his non-Arab appearance and German passport. He is curently living in Germany, he can´t be arrested because he commited no crime here, the government has impounded his passport and he has to report to the local police twice a day. He stated that he wanted to travel to the Middle East to join his group in the fight against Israel, but all border checkpoints have been warned not to let him out of the country.
Je Suis Charlie et je suis Ahmet aussi