taken by surprise. some of these images are extremably brutal. >> reporter: a chilling sights, cheering on the takeover of their city by the islamic state in iraq and syria. so brutal that even al qaeda has disowned them. far more worrying, they now control an arsenal of weapons left behind when iraq's army fled the scene. here you see a terrifying display, i.s.i.s. proudly showing off missiles they promise to use on their march towards baghdad. scary scenes like this are nothing new when it comes to i.s.i.s. the group that is perfected propaganda techniques, like this recent video, over an hour lounge, highlighting horrific killing scenes in iraq, deliberately videoed. bombings, executions, kidnappings, and worse. this production displayed glossy