One method,if my understanding is correct, is to attack by surpirse or to kill as many people as possible. By doing that, the killing of numerous/millions of people, usually end on on planes, buildings... That type of stuff. They usually do bombing of large areas. ~Hope this helped :)
Im not exactly sure but: - fear of arms and ammunition they cArry with them - theyre often masked which instigates fear of the unknown - theyre possibly popular for terrorist activities
