isis supporters myself, but one guy stood out. a 34-year-old american from sugar land, texas. warren christopher clark comes from a military family. but the muslim convert was a substitute teacher before coming to isis territory. he claims he just sold candy to support himself with isis and spent a lot of time reading. >> i would say most people, yeah, they want to go, they want to go fight or work in some area. i want to actually go see exactly what the group was about, you know what they were doing. >> his words rang a little hollow. how could he not have known? isis never made a secret of what it was about. in online videos, the group proclaimed its fanatical view of islam and documented the gruesome violence it inflicted on nonbelievers. >> you make it sound like you were a tourist visiting a normal country. >> yeah. >> but when you went in the spring of 2015, you'd seen all