Mason's Mary Ellen O'Toole, a former FBI profiler, said the trigger for the attack might not have been external, which will make it much more difficult to figure out. More from her appearance on CBS News' Face the Nation.
Mason's Mary Ellen O'Toole, a former FBI profiler, said the trigger for the attack might not have been external, which will make it much more difficult to figure out. More from her appearance on CBS News' Face the Nation.