How preposterous you leftist progressives really are when it comes to either your gullibility or your abject stupidity.  Police searching high and low, questioning if you can imagine, 3500 witnesses! Right! Looking for motivations. Where? In the stars? In a book of fables? The motivation dear "leaders" is an adherence and a love for jihadist Islamic terrorism and thus perpetrating acts as requested by ISIS officialdom who have been calling on Muslims and Islamic doctrine supporters to carry out acts wherever opportunity presents itself.  Duh! What we have here is another officialdom scenario to remove any relevance to the most relevant facts and they center on the doctrine of Islam and the many many passages in the Qur'an which call for death for infidels and betrayers of the principles of Mohamed. Security will try in the very same manner as dictated from above to ignore the illiberal beliefs brought into Western countries and continue to scurry about to hide those facts.