Jihadists demanded £80m ransom before beheading

US journalist James Foley was beheaded by IS jihadists. Picture: AP

News organisation GlobalPost, which employed Mr Foley, said the militants demanded the cash late last year after his abduction in November 2012.

He was later beheaded by an IS fighter thought to be British, whom captives called John, and who spoke with a south-east English accent, in the footage released earlier this week.

Hostages dubbed their three unnamed British captors “The Beatles” in reference to the pop group and named them John, Paul and Ringo.

United States officials said the demands were first sent in e-mails to Mr Foley’s family in New Hampshire, before being sent to his employer.

GlobalPost CEO Philip  Balboni indicated that European governments paid far less to have IS release their hostages. American policy prohibits the government negotiating with terrorists, including paying ransoms. More details of the hostage situation emerged last night, including confirmation that the Obama administration sent special forces troops to  rescue American captives in Syria, but that they did not find the hostages at a suspected location.

Last night, MI5 and British police were attempting to use advanced image analysis and voice-recognition software in an attempt to identify the masked militant who executed Mr Foley.

Despite being dressed head to toe in black, with only his eyes visible, experts have a plethora of clues. Forensic computer expert Sam Type said analysts will look at the clothing and boots worn, and the handgun held in a shoulder holster on the British jihadist, since “identifying where these items have been sourced may help determine where the perpetrators are located”.

Experts will also trawl social media postings on Facebook and Twitter and testimony from former captives. Peter Neumann, director of the International Centre for the Study of Radicalisation at King’s College London, said most of the hundreds of Western militants in Syria have Facebook or Twitter accounts.

“These are all young guys,” he said. “It’s a habit. It’s very hard for them to be disciplined.” But audio will be the primary source of interest. Experts will look for patterns of speech – rhythm, timing and timbre.

Elizabeth McClelland, a forensic speech analyst, told Sky News that the voice of “John” is “not the most routine voice, but not highly distinctive”. If the security services do have a reference sample, Ms McClelland said she would not be surprised if they could identify the killer.

John O’Regan, a linguist at the University of London’s Institute of Education, said the militant spoke with a “multicultural London English” accent but with more formal standard English pronunciation. He said that “there are enough features in the accent” to provide strong clues to his identity.

Richard Barrett, former head of counter-terrorism at MI6, said the militant would likely be recognised by “the intelligence community but also the community from which he comes.”

“He will have had many acquaintances and friends in the United Kingdom and those people will wish to see him brought to justice,” Mr Barrett said

Last night, another counter-terrorism expert said Islamist extremists are specifically using Western jihadists to guard and kill Western captives.

Dr Andrew Mumford, a politics expert at Nottingham University, said: “A picture is emerging that Isis is now explicitly using Western jihadists to take control and look after Western hostages. That is an important development.”

Reports say “John” was the main negotiator in ransom talks earlier this year. Some 11 hostages were eventually handed to Turkish officials after demands were met.

Dr Mumford said the killing showed the need for the UK government to tackle radicalisation of young British Muslim men.

He said: “Intelligence services, police, the military will be working together with politicians in order to ensure that counter-radicalisation must [take place] at the very beginning. It must not allow young men to be brainwashed in the first place.

“It is not just about mitigating the effects of men going to Syria; it is about stopping people from getting to the position where they want to go to places like Syria and Iraq in the first place. And that is a real challenge.”