The masked man who beheaded James Foley may have left several clues in the video unintentionally, experts said on Thursday.

With British Intelligence, Scotland Yard and Federal Bureau of Investigation working together, it may not be long before they identify the journalist's killer and produce leads for the rescue of other Islamic State hostages.

Like Us on Facebook

The video gave them valuable clues to work with. First is his distinct British accent. Second are his exposed body features, such as the bridge of his nose, eyes, skin color and his height contrasted to Foley's kneeling figure.

Of all these, the authorities' best lead is the man's voice, experts said. His accent was initially identified to be "multicultural London English."

They consulted with England's University of Reading phonetics professor, Jane Setter, who uses a voice analysis program to run and examine the voice.

The investigators are likely to look for a match from London police's voice recordings, forensic voice expert Martin Barry said. Barry is not working on the case, but he believes that the authorities will start with young delinquents in the East End, where most speakers of the accent are.

Barry said that the task will not yield results right away. Also, if there are no matches, then "effectively there is no way to be able to isolate the individual," he added.

However, authorities have other leads in the case. British newspapers reported an account by a former Islamic State hostage, who identified the man as "John" of possibly British nationality and among the three British members of the group.

The 500 British Jihadist who left the country to join the militants are also under investigation.

Former counter-terrorism chief Richard Barrett for Britain's Secret Intelligence Service or MI6 expressed optimism on the manhunt's success. British officials have also called on the public to identify the man should they know anything.

Foley was kidnapped in Syria in November 2012. Pentagon said on Wednesday that had a secret rescue mission for Foley and other hostages this summer but failed.

Tagsjames foley, British Intelligence, scotland yard, FBI, Foley's beheading, British accent killer, British Jihadist, voice analysis, MI6