UK & World News
James Foley's 'British' Killer: What We Know
As intelligence officials scramble to identify the black-clad killer of James Foley, few details have emerged.
This is what is known so far of the Islamic State (IS) militant who appears in a propaganda video that shows the beheading of Mr Foley.
According to a former hostage cited by the Guardian's Martin Chulov, the man calls himself John.
He appears to be left-handed and of average height and built.
Experts say the man speaks with a southeastern English accent. Some identified it as east London. Other possibilities include Essex and Kent.
The voice is one of the things experts will be looking at as they examine the video. Phonetic software will be employed to highlight obvious characteristics in his voice.
Mr Chulov told Sky News that, according to the former hostage, John is one of three Britons who act as the guards of foreign prisoners in the Islamic State stronghold of Raqqa.
Some former hostages refer to this group as "The Beatles".
John has been involved in negotiations with relatives of other hostages in the past. He is believed to have conducted negotiations that led to the release of 11 hostages earlier this year. The release was granted in exchange for huge amounts of cash, according to news reports.
His face has never been shown, either to hostages or to their relatives in Skype conversations during the negotiations.
John appears to be in charge of the group. Mr Chulov described him as the "leader of the pack".
Sky's Foreign Affairs Editor Sam Kiley said he appears to enjoy a high level of responsibility within the Islamic State. "This is the interface between IS and the outside world, it's through these hostages.
"Therefore this is a senior figure within it."
:: WELL EDUCATED
The Telegraph reported John was a well-educated, intelligent and highly committed member of IS. Mr Chulov said John likely to have been fighting with IS for at least a year.
:: POSSIBLE MOTIVES
Shiraz Maher, a senior researcher at the International Centre for the Study of Radicalisation, said Mr Foley's beheading is the first time IS has used a "directly confrontational approach" to the Western world.
Other experts noted that using an English-speaking militant in the brutal video is meant to scare the West by showing that IS has the ability to recruit from the West and hit Western targets.