Cameron Refuses to ID 'Jihadi John'

A masked, black-clad militant, who has been identified by The Washington Post newspaper as a Briton named Mohammed Emwazi, brandishes a knife in this still image from a 2014 video obtained from the SITE Intel Group, Feb. 26, 2015.

CAGE research director, Asim Qureshi, talks during a press conference saying that he saw strong similarities between the British-accented militant who has appeared in beheading videos and the man identified as Mohammed Emwazi, but because of the hood worn by the militant, “there was no way he could be 100 percent certain,” Feb. 26, 2015.

Two police officers walk outside a flat in London, February 26, 2015. Local media reported that the flat is the former home of Mohammed Emwazi, whom investigators believe is the "Jihadi John" masked fighter who fronted the Islamic State militant beheading videos.

Media stand outside a flat in London, February 26, 2015. Local media reported that the flat is the former home of Mohammed Emwazi, the "Jihadi John" masked fighter who fronted Islamic State militant beheading videos.

A journalist holds up a newspaper as she does a report outside a London home on February 27, 2015, where Kuwaiti-born computer programmer Mohammed Emwazi, identified by experts and the media as masked Islamic State militant "Jihadi John," is once believed to have lived.

A masked, black-clad militant, identified by The Washington Post newspaper as a Briton named Mohammed Emwazi, stands next to a man purported to be Steven Sotloff in this still image from a video obtained from SITE Intel Group website, Feb. 26, 2015.