throw off someone who you know is listening on your communications. reporter: isis in the sinai peninsula has shown bomb-making signals before and if isis is responsible for this, it would mark a significant step in their capabilities to launch further attacks. at this point, we don t have enough information to make our own determination about what exactly occurred but we do have enough information at this point to not rule out the possibility of terrorism. reporter: there is no indication so far that passengers or crew aboard the flight had any connection to terror groups so investigators are looking at a possible inside job. a not so sophisticated bomb planted by an employee at egypt s sharm el-sheikh airport. we re really kind of limited to either a timing situation or a barometric pressure switch bringing down an aircraft. reporter: tonight, egypt and