According to Dr Hans-Jakob Schindler, the arrests show that the risk of Hamas attacks in Germany remains high. "The initial investigations seem to confirm that the Islamist organization planted terrorists in Germany years ago," says the senior director and head of the Berlin office of the international Counter Extremism Project. Hamas operates with a high degree of professionalism. "The members of the terror cells, for example, try to act as inconspicuously as possible so as not to come to the attention of the security services." This includes not appearing as activists at propaganda events, for example. In addition, two of the suspected attackers who have now been arrested have taken German citizenship.