London ( CNN ) In his teenage years , there was little to set Mohammed Emwazi -- a quiet , hardworking boy with a few friends -- apart from his classmates . That 's according to Joanna Shuter , his former head teacher at Quintin Kynaston Community Academy in northwest London . Now 26 , Emwazi has gained international notoriety after being identified as the ISIS militant nicknamed `` Jihadi John '' who 's appeared in beheading videos of Western hostages . But in his school days , it was a different matter . When he joined Quintin Kynaston at 14 or 15 , he was little trouble himself but was the focus of some bullying . `` He was bullied a little , but because he was quiet and he was reserved ... generally he was fine , '' Shuter said . `` There were no massive behavior problems with him , and by the time he got into ... ( his last years ) he had settled , he was working hard , he achieved great grades for him , and he went to the university of his choice . '' He just did n't stand out as troubled , she said . `` If there had been any concerns about Mohammed , they would have been picked up , and we would have intervened and tried to support him in any way that we could have done . '' Born in Kuwait , but brought up in London from the age of 6 , Emwazi was one of the school 's many students from an immigrant background . The school 's intake is 70 % Muslim , said Shuter , with many students coming from large housing estates in what is a multicultural area of London . But its ethos was one of tolerance and integration , with all students encouraged to feel part of the school community . Staff made great efforts to get to know the 1,400 students in the school so that nobody would feel excluded or left behind , Shuter said . They also reached out to the sometimes insular , conservative Muslim communities that many of their students came from , she said , to try to help students who could feel torn between different cultures . Nonetheless , Emwazi was somehow drawn in by radical influences , most likely outside of school or through social media . And he was not alone . At least two other students who attended Quintin Kynaston also allegedly later turned to Islamist extremism . One , Mohammed Sakr , only overlapped at the school by a few months with Shuter . He was reportedly killed in a U.S. drone strike in Somalia in 2012 . `` He was very outgoing , jolly , sporty kind of person and fun , '' Shuter said . Shuter sees social media as the greatest danger facing young people and their families today . `` I think social media is terrifying because it does have the power to influence young people in a way that as adults we have no power to control , '' she said . She still finds it hard to believe that Emwazi could be the apparent killer with the London accent recorded on ISIS videos . `` My blood just ran cold , '' she said of when she first heard the news . `` When I hear the name , I just find it incredible to marry what I 've clearly seen on the TV with the person that I knew . It literally makes the hairs on the back of my neck stand up . I ca n't believe what has happened to him and the influences that clearly have completely changed him . `` I think it 's horrific , the idea that a young man like that could become somebody that people say is the poster boy for ( ISIS ) . I just think it 's shocking . '' The London-accented voice is all too familiar to anyone who 's watched the videos released by ISIS of the killing of Western hostages . CAGE , a London-based advocacy group that worked with Emwazi , has released audio of a phone conversation from 2009 in which he talks about members of the UK security services questioning him . They asked about his attitude toward the July 7 , 2005 , terror attacks in London and the 9/11 attacks on the United States , he says . `` We 're going to keep a close eye on you , Mohammed , '' he alleges they told him . CAGE has painted a picture of a young man driven to extremism by unwarranted harassment by security services . It says emails he sent the group paint a picture of a desperate man hounded by authorities who saw his plans for a new life crumble as he tried unsuccessfully to get help . But some analysts say the emails are only part of the story , arguing that investigators targeted Emwazi because they already saw he had links with terrorist groups .
EmwaziMohammed Emwazi 's 's ex-head teacher says he was a quiet boy , slightly bullied at school . She says there was no sign during his school years that he was turning to radical Islam . Advocacy group releases audio with Mohammed Emwazi 's 's complaints of security services ' questioning .