Story highlights A video claims to show the killing of Mohamed Said Ismail Musallam 
 
 Musallam's family says ISIS recruited him 
 
 ISIS claims the 19-year-old is an Israeli spy 
 
 Jerusalem (CNN) A newly released ISIS video shows a child shooting a man the group claims is an Israeli spy. 
 
 The video identifies the man as 19-year-old Mohamed Said Ismail Musallam, an Israeli citizen of Palestinian descent. 
 
 In the video, ISIS shows Musallam's Israeli passport and claims he's an agent sent to infiltrate the group. The 19-year-old's family told CNN Tuesday that he had no ties with the Mossad, Israel's spy agency, and had, in fact, been recruited by ISIS. 
 
 "Mohamed told me and his brother that ISIS took him," according to Said Musallam, his father. "They sent him money through the Western Union. They said you will have girls, money, cars, villas, paradise, but afterwords he discovered that there is nothing." 
 
 It wasn't long before Musallam's family members didn't recognize him when they talked to him on Skype. The man they knew as a kind and funny brother and son who was once a volunteer firefighter had grown a long beard and was carrying a rifle. 
 
 Read More ||||| The mother of Muhammad Musallam, an Israeli Arab held by Islamic State in Syria as an alleged spy, weeps as she holds his photograph in her East Jerusalem home February 12, 2015. 
 
 BEIRUT A video posted online by Islamic State militants on Tuesday showed a boy fatally shooting Muhammad Musallam, an Israeli Arab accused by the group of having signed up as a jihadi to spy for Israel's intelligence service. 
 
 The video, published by the group's Furqan media outlet, showed Musallam, 19, sitting in a room wearing an orange jumpsuit, talking about how he had been recruited and trained by Mossad. He said his father and elder brother had encouraged him. 
 
 After that, it showed Musallam being escorted to a field and then being shot in the head by a boy, described by an older, French-speaking fighter as one of the "cubs of the caliphate". 
 
 Reuters could not immediately verify the authenticity of the footage, which also appeared on Twitter feeds used by Islamic State supporters. 
 
 Israeli security officials said they were aware of the video but could not confirm that it was authentic. 
 
 The video, which was about 13 minutes long, showed Musallam on his knees as he listened to the older fighter delivering the verdict in French. 
 
 Then the boy, wearing a military uniform and armed with a pistol, stands face to face with Musallam and fires one bullet into his forehead. After Musallam collapsed, the child shot him three more times and chanted "Allahu Akbar!" (God is greatest). 
 
 In the video, Musallam repeated what he had said last month in an interview published by the group's English language magazine Dabiq, in which he said he had joined Islamic State to report to the Israelis on weapons caches, bases and Palestinian recruits. Israel and his family denied that he was an Israeli spy. 
 
 "I tell my father and my son: Repent to God. I say to the spies who spy on Islamic State: You will not be successful, they will expose you," Musallam said in the latest video, in Arabic. 
 
 An Israeli security official had said Musallam went to Syria to fight for Islamic State in October last year. 
 
 Musallam's father has denied his son was a spy, saying a month ago that his son had gone missing while on a tourist trip to Turkey. 
 
 Said Musallam and the youth's mother, Um Ahmad, wept at their home in East Jerusalem when they learned of his death. Clutching her son's photograph, Um Ahmad told reporters: "A spy of 19? How is that possible? Why would he have gone there if he were a spy?" 
 
 Said Musallam said his son had been trying to return home when he was captured. He accused the militants of forcing his son to say he was a spy before killing him just for show. 
 
 "Mohammad was told by them to say about himself that he works for the Israelis," Said Musallam said. "They took him as a victim, only to show the world, so the world would be afraid of them." 
 
 (Reporting by Mariam Karouny and by Ali Abdellati in Cairo; Editing by Kevin Liffey and Ken Wills) ||||| Image copyright AFP Image caption Mohammed Musallam's parents said he had he left for Syria four months ago without telling them 
 
 Islamic State (IS) militants have posted a video online which appears to show a young boy shooting dead an Israeli Arab prisoner. 
 
 The man, identified as Mohammed Said Ismail Musallam, was accused by IS of working for Israel's Mossad foreign intelligence service. 
 
 The 19-year-old left his home in East Jerusalem for Turkey last year, apparently intending to fight in Syria. 
 
 Israeli officials and Mr Musallam's family denied he was an Israeli spy. 
 
 The video footage has not been independently verified and Israeli officials said they could not confirm its authenticity. 
 
 'Own initiative' 
 
 Mr Musallam's family said he had left for Turkey four months ago without telling them. Soon after his departure, he told his brother that he planned to join IS in Syria. 
 
 A spokesman for the Shin Beth security service also told the AFP news agency that he had left home "on his own initiative". 
 
 At the scene: Yolande Knell, BBC News, East Jerusalem 
 
 Comforted by her remaining three sons, Umm Ahmed sits weeping for 19-year-old Mohammed Musallam. 
 
 She recalls her shock when she discovered that he had run away to join Islamic State fighters in northern Syria. "They recruited him through the internet," she says. "They told him: 'Come and we'll give you a house, money, you can get married - we have beautiful girls.'" 
 
 By the time Mohammed contacted his family from Raqqa late last year, the clean-shaven teenager had grown a beard and was carrying a Kalashnikov rifle. But his father says he had become disillusioned and wanted to return home. 
 
 Said Musallam tells me that Mohammed, an Israeli citizen, tried to escape but was caught and accused of being an Israeli spy. 
 
 "There was no way they were going to let him go," he says. "He'd been there for three months and seen their weapons. They said: 'He betrayed us, we'll ruin his reputation.' And that's what they did." 
 
 In February, the IS magazine Dabiq carried a long interview with Mr Musallam which contained what purported to be a confession that he had been sent by Israel to infiltrate the jihadist group. 
 
 The BBC's Kevin Connolly in Jerusalem says the article gave sketchy details about his alleged training and mission, but its publication was a clear signal that he had fallen foul of the group and was in clear danger. 
 
 Image copyright AFP Image caption Mohammed Musallam sent his family a photo of himself dressed in military fatigues, holding a rifle 
 
 On Tuesday evening, Islamic State's Furqan media outlet published a 13-minute video showing a young man, identified as Mr Musallam, sitting in a room wearing an orange jumpsuit, talking about how he was recruited and trained by Israeli intelligence. 
 
 He is later shown kneeling in an empty field, facing the camera. Behind him stand two figures in camouflage fatigues, one of whom appears to be a boy. 
 
 The boy appears to shoot the kneeling figure in the head with a handgun and then to fire further shots into the body. 
 
 The video then carries a warning from an older, French-speaking militant aimed at the Jewish people. 
 
 French media and IS supporters identified the older militant as Sabri Essid. He is reportedly a half-brother of Mohamed Merah, who killed three unarmed French soldiers, a rabbi and three small children at a Jewish school in France in 2012. ||||| The video, released through Isis’s official propaganda outlet al-Hayat Media, shows two men who it claims are “agents recruited by Russian intelligence” apparently being shot in the desert by a child who is thought to be around 10 years old. 
 
 It comes just a day after another video showed a child aged around 14 apparently carrying out a suicide bombing in the Iraqi province of Salahuddin. 
 
 A previous video showed a young boy who Isis claimed took part in a suicide bombing And while the apparent execution could not be independently verified, experts suggested that the increased use of children in the atrocities it films represented “a departure from past norms”, even by Isis standards. 
 
 The new video is entitled “Uncovering an enemy within”, and has been published by the branch of Isis which specialises in making propaganda videos for an international audience. 
 
 Including captions in Arabic and English, it claims the two men are “FSB agents”, offered money to “gather information about fighters and send the information to Russia”. 
 
 After they are shown “confessing” to the camera, a separate part of the video shows the two men on their knees in the desert before a militant and a boy who can be no more than 10 years old. 
 
 The militant says the men are now “in the custody of the lion cubs of the caliphate”, before the child steps forward and appears to shoot the men. 
 
 The same child has appeared in previous Isis videos, and also features in a clip at the end of the most recent video that appears to have been shot some time earlier. 
 
 Charlie Winter, a researcher for the anti-extremism thinktank Quilliam, said: “Whether it is real or staged, [Isis] used a young child in this video for the shock factor, and the shock factor alone. 
 
 “Its propagandists have done it before – showing images of children training as soldiers and being kicked in the stomach in martial arts drills – but this latest video marks a departure from past norms.” 
 
 The video comes amid increased speculation over the blurring of lines between disparate militant groups like Isis and al-Qaeda in the Arabian Peninsula (AQAP), particularly in the wake of the Paris shootings. 
 
 And while many social media users speculated as to whether the apparent execution was genuine, Isis supporters shared it as a warning to “you who sent spies”. 
 
 One Isis-affiliated account under the name Abu Marthad al-Muhajir tweeted: “This is not al-Qaeda, this is the Islamic State, O you filthy stupid Marxists of Russia. This is your destiny.”
– More horror from ISIS' media wing: A boy who appears to be no older than 12 shoots dead an alleged Israeli spy in the latest video released by the militants. The video shows an older, French-speaking militant threatening Jews before the boy shoots a man identified as Muhammad Said Ismail Musallam, a 19-year-old Israeli Arab, in the forehead, the BBC reports. The older militant describes the boy as a "lion cub of the caliphate" in the video, which also shows Musallam confessing to spying on ISIS for Israel, reports Reuters. Israeli authorities say Musallam was not a spy but an ISIS recruit, which his father confirms to CNN from his home in East Jerusalem. The teenager was promised "girls, money, cars, villas, paradise," but tried to leave when he "discovered that there is nothing" and was captured as he tried to return home, the father says. Separately, an ISIS defector now in Turkey has explained why some hostages seem calm in beheading videos the group has released. In an interview with Sky News, the defector claims foreign hostages were subjected to many filmed mock executions before they were finally killed, and part of his job as a translator for ISIS was to convince the Westerners that they would not be harmed and the videos were only to put pressure on their governments.