The masked militant first appeared in numerous gruesome videos put out by Islamic State, as Lucy Manning reportsEmwazi first appeared in a video last August, when he apparently killed the US journalist James Foley. Dragana Haines, wife of slain hostage David: "I hope he will be caught alive... He needs to be put to justice". He was later thought to have been pictured in the videos of the beheadings of US journalist Steven Sotloff, British aid worker David Haines, British taxi driver Alan Henning, and American aid worker Abdul-Rahman Kassig, also known as Peter.
Mohammed Emwazi timeline:
- 1988: Born in Kuwait, moves to UK in 1994
- 2009: Completes computing degree at University of Westminster
- Aug 2009: Travels to Tanzania with two friends for safari but refused entry at Dar es Salaam. Put on flight to Amsterdam. After questioning there, returns to Dover
- Sept 2009: Travels to Kuwait to stay with father's family
- July 2010: Returns to UK for short stay but told he cannot return to Kuwait as visa denied
- 2012: Passes Celta English language teaching course
- 2013: Changes name by deed poll. Tries to travel to Kuwait but is stopped. Disappears. Parents report him missing. Police tell family four months later he has entered Syria
In a news conference, Asim Qureshi, the research director of the London-based lobby group Cage, which had been in contact with Emwazi over a number of years, explained how he had been approached by the Washington Post for the story and detailed the difficulties Emwazi had had with security services in the UK and overseas.
Mr Qureshi said Emwazi, who is understood to be about 27, had been "extremely kind, gentle and soft-spoken, the most humble young person I knew". He said he could "not be 100% certain" Jihadi John was Emwazi although there were "striking similarities".
Emwazi then ended up flying to Amsterdam, in the Netherlands, where he claimed to be met by British intelligence agents from MI5 who accused him of trying to travel to Somalia, where the jihadist group al-Shabab operates. He denied the accusation and said the agents had tried to recruit him before allowing him to return to the UK.
US and British counter-terrorism officials discovered the identity of "Jihadi John" as far back as last September. The FBI, Britain's MI5 and other intelligence agencies used a combination of voice recognition software, interviews with former hostages and on-the-ground research in London to build up a profile of the man now revealed to be Mohammed Emwazi.
They have always declined to reveal the name for "operational reasons". Now that it's out in the public domain, it's emerged that Emwazi was well-known to MI5 and that it even tried to recruit him as an informer, years before he went off to Syria to eventually join Islamic State.
The practice by intelligence agencies of approaching jihadist sympathizers to work for them is likely to continue. It's believed both Britain and the US have informers inside the Islamic State "capital" of Raqqa. Yet this seems to have been little help in stopping the actions of Mohammed Emwazi, or bringing him to justice.
Emwazi later moved to Kuwait, where he got a job at a computer company. But on a visit to London in 2010, he was detained by British counter-terrorism officials and prevented from flying back to Kuwait, his friends said.
"I had a job waiting for me and marriage to get started," Emwazi wrote in a June 2010 email to Cage.
"[But now] I feel like a prisoner, only not in a cage, in London," he added, "a person imprisoned and controlled by security service men, stopping me from living my new life in my birthplace and country, Kuwait."
He said he did not know what had happened to Emwazi, adding: "When we treat people as if they are outsiders they will inevitably feel like outsiders - our entire national security strategy for the last 13 years has only increased alienation. A narrative of injustice has taken root."