Man with British nationality appears in video of Khan 's beheading . The source said `` it 's too premature '' to know with any certainty just one week since the video of Sotloff 's death was published . ` ` They have a pretty good idea of who it may be , '' a U.S. official says . But officials say they are n't 100 % certain of man 's identity .
Man with British nationality appears in video of Khan 's beheading . ` ` They have a pretty good idea of who it may be , '' a U.S. official says . But officials say they are n't 100 % certain of man 's identity .