- 'Jihadi John' is Mohammed Emwazi, a Kuwaiti-born Londoner
- Friends remember him as the typical boy next door
- He's thought to be seen in a video demanding $200 million to spare two Japanese journalists
(CNN)For more than a year, "Jihadi John" has been something of a nightmare for the West.
But now the masked public face of ISIS may be gone, possibly the victim of a U.S. drone strike, the Pentagon announced.
It wasn't immediately clear whether the strike was successful. But a senior U.S. official said authorities are confident the strike killed him.
This is what we know about the man behind the mask.
Mohammed Emwazi is a Kuwaiti-born Londoner.
He is believed to have traveled to Syria in 2012 and later joined ISIS there.
Emwazi was born in Kuwait in 1988 and he moved to the UK with his parents, Jasem and Ghaneya, and sister when he was 6, according to CAGE, an advocacy group for those affected by terrorism investigations.
The family settled in west London. Emwazi's father is reported to have worked as a taxi driver while his mother stayed at home to look after Emwazi and his siblings.
Many of those who grew up with him have told British news organizations they remember Emwazi much differently: as the typical "boy next door," a popular kid who loved football, pop music and The Simpsons.
He is reported to have attended St Mary Magdalene Church of England Primary School, in the Maida Vale distict in west London. After leaving St. Mary Magdalene, he is believed to have moved on to the Quintin Kynaston Academy, in neighboring St. John's Wood.
A former teacher told Britain's Channel 4 News that Emwazi was "a diligent, hardworking, lovely young man. Responsible, polite, quiet. He was everything that you'd want a student to be."
He studied at the University of Westminster in London, graduating in 2009 with a degree in computer programming, according to CAGE.
With so much going for him, what inspired Emwazi to join ISIS?
Guesses depend on whom you ask.
Some terrorism experts said Emwazi's history shows someone who'd been on a path toward extremism for years.
But CAGE said that, if he is the man who has appeared in ISIS videos, it shows that the tactics of British authorities radicalized him.
Friends of Emwazi said they believed he started down the road to radicalization when he traveled to the east African nation of Tanzania in 2009, the Washington Post reported this year.
He was supposed to be going on safari but he was reportedly detained on arrival, held overnight and then deported.
He was also detained by counterterrorism officials in Britain in 2010, the Post said.
Authorities have not disclosed the reasons for those reported detentions.
Alienation to ISIS?
There are "striking similarities" between Emwazi and the man known as "Jihadi John," according to Asim Qureshi, CAGE's research director.
If Emwazi is indeed Jihadi John, Qureshi said, that makes him sad. But in some ways, he said, it's not surprising.
Many Muslims feel alienated in their society, as did Emwazi, Qureshi said.
"When are we going to finally learn if we treat people as if they're outsiders ... they will look for belonging elsewhere?" Qureshi asked. "Our entire national security strategy for the last 13 years has only increased alienation."
The Washington Post's report includes emails Emwazi purportedly wrote after British counterterrorism officials detained him and stopped him from flying to Kuwait.
"I had a job waiting for me and marriage to get started," he wrote in a June 2010 email to Qureshi, the Post reported.
But now "I feel like a prisoner, only not in a cage, in London. A person imprisoned & controlled by security service men, stopping me from living my new life in my birthplace & country, Kuwait," the email said.
CAGE points the finger at British security services, which it says have "systematically engaged in the harassment of young Muslims, rendering their lives impossible and leaving them with no legal avenue to redress their situation."
Only half of the story?
Haras Rafiq, managing director of the Quilliam Foundation, a UK-based counter-extremism think tank, said CAGE was pointing in the wrong direction.
It's clear Emwazi had been radicalized before 2010, Rafiq said. And he said the intelligence agencies that stopped Emwazi from traveling to Tanzania believed there was evidence he intended to join the extremist group Al-Shabaab in Somalia.
Haras said it was "very upsetting that an organization like CAGE would spin this in the way that they've done," by blaming intelligence agencies.
Former CIA counterterrorism analyst Philip Mudd told CNN that blaming radicalization on alienation was oversimplifying Emwazi's case.
"We're only seeing half of this story," he said. "The government doesn't spend the resources and take the risk, the legal risk of pulling somebody aside, preventing them from traveling, searching through their luggage, just because somebody looks funny. There is something else going on here, in terms of whatever triggered the government to undertake this investigation, that we're missing here."
The masked, black-clad figure believed to be Jihadi John appeared to be the ISIS militant shown in a January video, demanding a $200 million ransom to spare the lives of two Japanese journalists. A similar figure appeared in at least five previous hostage videos.
The man's reported background offers some clues as to why he might have been recruited, said Sajjan Gohel, director of international security at the Asia Pacific Foundation.
"We know that ISIS recruits a lot of Westerners who are skilled in new media, understanding of the Internet, because they use that as their platform as an oxygen of publicity," Gohel said.
But by not revealing his name for operational reasons, one expert said, officials may have created another problem.
"It created more speculation in the media," he said. "In some ways, the nom de guerre of Jihadi John gave this individual a form of notorious celebrity."
Emwazi, who speaks English, was frequently seen in hooded hostage videos carrying out violent beheadings.
For periods at a time this year, Emwazi was not seen in hostage videos, though U.S. officials told CNN in July that they had learned that he was alive and hiding near Raqqa.
Analysts describe him as grotesque and fond of sadistic torture techniques, with one former hostage recounting last month how his captor made him dance the tango with him.