LONDON -- The man in the black balaclava who seems to have beheaded several foreign hostages in Islamic State videos has been identified by British security services as Mohammed Emwazi, a British citizen from London.
Known in the news media as "Jihadi John," he is said to have been born in Kuwait and traveled to Syria in 2012. His name was first published Thursday on the website of The Washington Post.
The story was confirmed by a senior British security official, who said that the British government had identified Emwazi some time ago but had not disclosed his name for operational reasons.
Emwazi, 27, grew up in West London and graduated from the University of Westminster with a degree in computer programming.
He first showed up in Islamic State videos in August, when he appeared to behead the American journalist James Foley and deliver threats against the West. The actual execution was not included in the video.
The same man was apparently seen in the videos of the beheadings of a second American journalist Steven J. Sotloff; the British aid worker David Cawthorne Haines; the British taxi driver Alan Henning; and the American aid worker Peter Kassig. Last month, he appeared in a video with Haruna Yukawa and Kenji Goto, both Japanese hostages, shortly before they were killed.
Scotland Yard refused to confirm the identification, and the prime minister's office had no comment.
"We are not going to confirm the identity of anyone at this stage or give an update on the progress of this live counterterrorism investigation," said Richard Walton from the Metropolitan Police Counter Terrorism Command.
The British prime minister, David Cameron, has said that he has viewed the videos with horror. Speaking in November, he said, "You should be in no doubt that I want Jihadi John to face justice for the appalling acts that have been carried out in Syria."
Emwazi apparently became radicalized after being detained by the authorities after a flight with friends to Tanzania in 2009 for a safari after graduation. He was detained and accused by British intelligence officers of trying to make his way to Somalia.
Friends of his told The Post that Emwazi and two others - a German convert to Islam named Omar and another man, Abu Talib - never made it to the safari. On landing in Dar es Salaam, Tanzania, in May 2009, they were detained by the police and held overnight before eventually being deported, they said.
Asim Qureshi, a research director at CAGE, a British advocacy organization opposed to what it calls the "war on terror," met with Emwazi in the fall of 2009. "Mohammed was quite incensed by his treatment, that he had been very unfairly treated," Qureshi told The Post.
Emwazi then moved to Kuwait, his birthplace, working for a computer company, and he returned to London at least twice, Qureshi said. British counterterrorism officials detained Emwazi in June 2010, fingerprinting him and searching his belongings.
"I had a job waiting for me and marriage to get started," he wrote in a June 2010 email to Qureshi. But now, "I feel like a prisoner, only not in a cage, in London. A person imprisoned & controlled by security servicemen, stopping me from living my new life in my birthplace & country, Kuwait."
Qureshi said he had last heard from Emwazi in January 2012. "This is a young man who was ready to exhaust every single kind of avenue within the machinery of the state to bring a change for his personal situation," Qureshi told The Post. In the end, Emwazi felt "actions were taken to criminalize him, and he had no way to do something against these actions."
Shiraz Maher, a senior fellow at the International Center for the Study of Radicalization and Political Violence, at King's College London, said on Twitter that Emwazi, "middle class & educated, demonstrates again that radicalization is not necessarily driven by poverty or social deprivation."
British officials estimate that there are at least 500 homegrown militants fighting in Syria and Iraq, some of whom have returned to Britain.
Hostages gave Emwazi the name John as he and other Britons had been nicknamed the Beatles; another of their captors was labeled George. They were said by hostages to be part of a team guarding Western hostages, first in Idlib, Syria, and then in Raqqa, the de facto capital of the Islamic State.