the dense crowd. >> the very high bomb blast sound and then i saw a lot of hands, legs without their bodies. >> at least 170 afghans and 13 u.s. troops died after an isis suicide bomber struck outside kabul airport. the pentagon investigation of the attack released friday said everyone died in the blast. >> the single explosive device killed at least 170 afghan civilians and 13 u.s. service members. by explosively directing ball bearings through a packed crowd. >> reporter: a review unearthed this brief glimpse of the bomber. cnn spent four months investigating the incident reviewing medical records and analyzing video, photos, and audio of the scene and speaking to over 70 witnesses or families of the dead, doctors, hospitals staff and survivors who insist some of the dead and wounded were shot.