THE beheading of American journalist, James Foley, at the hands of ISIS militants shocked the world but forensic experts have revealed the video was probably staged, with the murder happening off camera.

The UK Times reported that an international forensic science company, which has worked for police forces across Britain, said there is no question Foley was beheaded but that camera trickery and post-production techniques look to have been used.

“I think it has been staged,” said one expert in visual forensics, after he was commissioned by The UK Times to examine the footage.

“My feeling is that the execution may have happened after the camera was stopped.”

Aymenn al-Tamimi, a fellow at the Middle East Forum think-tank, said over the years ISIS militants have improved the production quality of their videos.

The analysis by experts has highlighted a number of inconsistencies that could suggest that the beheading of Foley, which was seen on the video, was not his actual death.

Firstly, no blood can be seen, even though the knife is drawn across the neck area at least six times. Secondly, sounds allegedly made by Foley do not appear consistent with what may be expected.

The forensic analysis expert said that no incision could be seen on Foley’s neck, though the right hand of the jihadist partially blocked the shot.

While the forensics company, which asked to remain anonymous, did not reach a definitive answer they did conclude that at some point an execution of Foley did take place.

This comes as a heartbreaking last letter from Foley to his family has been revealed on the Free James Foley Facebook tribute page.

While Foley was not permitted to send the letter, a fellow hostage, Danish photographer Daniel Rye Ottosen, memorised it word for word.

The 25-year-old spent 13 months imprisoned with Foley and when released in June his first call was to Foley’s mother, Diane, where he dictated every word.

British Intelligence has identified the ISIS killer of American, Abdel Majed Bary of London, England! pic.twitter.com/FEEy1iHk0J — DR. TWEET, PhD (@Callisto1947) August 24, 2014

Foley describes fond memories with his family and how he and the eighteen other hostages being held with him are coping.

“I know you are thinking of me and praying for me. And I am so thankful. I feel you all especially when I pray. I pray for you to stay strong and to believe. I really feel I can touch you even in this darkness when I pray,” Foley said in the letter.

“I have had weak and strong days. We are so grateful when anyone is freed; but of course, yearn for our own freedom. We try to encourage each other and share strength. We are being fed better now and daily. We have tea, occasional coffee. I have regained most of my weight lost last year.”

Foley goes on to describe his hopes of attending his sister’s wedding and his plans to take his grandmother out when he returns home.

“Grammy, please take your medicine, take walks and keep dancing. I plan to take you out to Margarita’s when I get home. Stay strong because I am going to need your help to reclaim my life.”

The full letter can be read here.

Today, his family has prayed for the safety of his fellow hostages as hundreds gathered for a mass to celebrate his life as a witness on the front line.

The mass at the church of Our Lady of the Rosary in Rochester, New Hampshire was overseen by the Bishop of Manchester Peter Libasci - who read a message from the Pope.

“I want to celebrate a life of bearing witness,” his mother Diane said.

“So many people are suffering in the Middle East right now, and there are many hostages being held captive, so this is a mass for all of those who are hoping for peace, and also in Jim’s memory.”

Diane’s husband John said: “We pray for the surviving hostages and in particular Steven Sotloff. We’re just hopeful that something can be done to avoid Jim’s end.”

The couple were given a prolonged standing ovation by several hundred well-wishers after the service, many clearly moved by their dignified response after the cruel end to a long ordeal.

Mrs Foley revealed that her family had been distressed when James, who had been held hostage for several weeks in Libya, decided to go back to first Libya then to Syria.

She recalled in late 2012, before his last departure, pleading with him to “at least stay until Christmas”.

“He said, ‘Oh, Ma, I’ll be back for Christmas, but I’ve got to go.’ He felt he had work to do,” she said.

Yesterday, British security services MI5 and MI6 reportedly identified a British hip-hop artist as the key suspect in the hunt for the killer who beheaded Foley.

The Sunday Times newspaper said Abdel-Majed Abdel Bary, from Maida Vale in West London, had become a crucial part of the investigation.

The paper attributed the information to “senior government sources.”

Bary, 23, is the son of an Egyptian-born militant who is awaiting trial on terror charges in New York tied to the deadly 1998 bombings of embassies in Kenya and Tanzania.

Former hostages held by ISIS have said he is one of several jihadists they nicknamed “the Beatles” due to their British accents, with two of his cronies referred to as “George” and “Ringo.”

Bary — who recently tweeted a photo of himself holding up a severed head — was among three Brits identified as possibly being the masked killer known as “John”.

In June, The Sunday Times revealed a threat made by Bary on Twitter. “The lions are coming for you soon you filthy kuffs (infidels),” he wrote. “Beheadings in your own backyard soon.”

Bary, who went to Syria last year to fight in its bloody civil war, has a build, skin tone and ­accent all similar to those of “John,” according to The Telegraph.

Before becoming a jihadist, he was an aspiring rapper known as “L Jinny,” whose music was played on BBC Radio 1.

Bary also appeared in music videos posted on YouTube for songs titled Overdose, Flying High and Dreamer.

But he was reportedly radicalised by followers of firebrand ­Islamic preacher Anjem Choudary and walked out of his family’s plush West London home last year, saying he was “leaving everything for the sake of Allah.”

Earlier this month, he was seen in a photo posted to Twitter wearing camouflage clothing and a black balaclava while holding a severed head with his left hand — the same hand “John” is seen using to draw a knife across Foley’s throat in his execution video.

Also under investigation are Abu Hussain Al-Britani, 20, a computer hacker from Birmingham, and Abu Abdullah al-Britani, in his 20s, from Portsmouth, the MailOnline reported.

Mail Online reported that al-Britani was jailed in 2012 for stealing personal information from former UK Prime Minister Tony Blair.

Since joining ISIS’ brutal campaign in Syria al-Britani, real name Junaid Hussian, has worked to fund the ISIS war chest by mounting jihadist cyber attacks on British banks and celebrities.

Abu Abdullah Al-Britani, meanwhile, is active on social media using Twitter to post pro-ISIS propaganda. According to Mail Online, he is believed to be behind an account on the ask.fm social media site giving young people advice on how to travel to Syria and Iraq and encouraging them to join the jihad.

Other possible identities for “John” include the brother of a British doctor once charged with kidnapping two Western war correspondents, and a former gang member who converted to Islam and travelled to Syria, Britain’s Telegraph newspaper reported.

A dozen American counterterrorism experts are expected to fly to the UK “within days” to help identify Foley’s killer, the Daily Mail reported.