A classmate of Mohammed Emwazi - the Londoner unmasked as "Jihadi John" - has told Sky News that "nothing in his high school could have left him radicalised".
The fellow pupil of the Quintin Kynaston academy, who was two years older than Emwazi and does not wish to be named, believes the IS militant's education beyond high school may be responsible for his transformation into a cold-blooded killer.
"It wasn't like university where you'd have speakers coming over from certain societies to give talks," he said. "I suppose there was potential for him to be groomed, that is a possibility. But at the time, at secondary school, he was like any of us."
Emwazi went on to study at the University of Westminster between 2006 and 2009 - finishing his computer programming degree in the same year he was reportedly questioned by an MI5 officer in Amsterdam, accused of attempting to travel to Somalia to join a terror group.
According to the classmate, there was nothing to suggest Emwazi was religious during his teenage years. He was quiet, rarely made eye contact, and always wore a baseball cap - but was known to get into the occasional fight.
"He wasn't someone who was loud, talkative and provocative," the ex-pupil added. "There were more violent people than him."
There has been widespread shock at Emwazi's old high school following his apparent involvement in a series of Islamic State videos which show the gruesome beheadings of Western aid workers and journalists.
The classmate, who has watched some of the videos, continued: "Something has gone wrong somewhere - whether in the UK, or when he went abroad.
Gallery: Jihadi John's University Academic Record
Mohammed Emwazi, aka Jihadi John, studied a computing course at university. Sky News has exclusively obtained his student record
His file shows mostly middling academic grades for his course modules. He graduated with a lower second (2.2) degree