'We won't rest until there's a bullet between his eyes' - daughter of Jihadi John victim David Haines

'Jihadi John' has has featured in six Isis videos. Photo / AFP

The daughter of one of Jihadi John's victims said her family will not rest until there is a bullet between the killer's eyes as his identity was revealed for the first time today.

The Islamic State executioner was today named as Mohammed Emwazi, a university graduate from London who was able to flee to Syria despite being on an MI5 terror watch list.

Emwazi, of Queen's Park, west London, was allegedly spoken to three times in one year by police and security services in Tanzania, the Netherlands and Britain.

The 26-year-old, who studied computer programming at the University of Westminster, is said to have travelled to the Middle East three years ago and later joined Isis.

Tonight, the daughter of David Haines, one of the killer's beheading victims, has said she would only "feel closure and relief once there's a bullet between his eyes".

Bethany Haines lost her father when he was brutally executed by Emwazi. The 44-year-old Scottish aid worker was seized in Syria in 2013, and then murdered last September.

She welcomed the fact Emwazi's name had now been made public and said: "It's a good step but I think all the families will feel closure and relief once there's a bullet between his eyes."

The 17-year-old told ITV News she did not blame the security services for not preventing her father's murder and added: "If they'd known his name earlier they could've stopped him going - but they can't and once he's captured I think there will be a lot of happy faces."

Emwazi has also featured in the execution videos of British aid worker Alan Henning, US journalists James Foley and Steven Sotloff, Japanese reporter Kenji Goto and Syrian soldiers.

His identity was confirmed this afternoon by two US government sources. Whitehall sources meanwhile told MailOnline that Emwazi had been known to security services for at least weeks, probably months, but had not made public his identity because the priority was trying to find him.

Arabic speaker Emwazi has one brother and two sisters, and first moved to Britain aged six.

The son of a minicab driver, he was reported to have occasionally prayed at a mosque in Greenwich, south-east London.

David Haines was beheaded in an Isis video. Photo / Supplied

A source who claims to have met with Emwazi in Syria told Channel 4 news that they believed Emwazi initially joined the Migrants Brigade or Mujahideen in 2012.

Emwazi was believed to have been based in Syria's Idlib Province and then outside Aleppo, before going on to join Al-Nusra and finally ISIS.

The source described him as personable, sometimes light-hearted but also determined that jihadi fighters were seen in the media as people to be afraid of.

They also described Emwazi as a keen video games player, and a martial arts practitioner.

Ominously, they also described an occasion when Emwazi - as one of the best Arabic speakers in the brigade of foreign fighters - led the interrogation of a man who was questioned before being badly beaten.

After graduating from university in May 2009, Emwazi flew to Tanzania with friends apparently on a safari - but was arrested by police upon landing in Dar es Salaam and sent back to Britain.

En route he stopped in Amsterdam, where he claimed to have been accused by an MI5 officer of trying to reach Somalia, home of the militant group Al Shabaab.

Emwazi claimed to have been harassed and intimidated by security services - and even complained to the Independent Police Complaints Commission.

He alleged an agent from MI5 knew "everything about me; where I lived, what I did, and the people I hanged around with" and claimed the organisation attempted to "turn" him to work for them.

Tonight, a neighbour of the family on the estate where they lived said he recalled an incident where Emwazi watched on as his younger brother was attacked by a gang.

Unemployed James Beker, 46, said: "I remember once the younger brother was being beaten up badly outside the flat by a gang of boys and the older brother just watched.

"I came down stairs and said to the older one, 'Why did you let your brother get beaten?' and he said 'I'm not bothered'. The whole thing was strange, why would you let your brother get beaten?

"The younger brother, who got beaten, was about 16 or 17. The older one was between 22 and 27.

"The incident happened around two years ago I think. It's the only incident I remember, I don't ever really remember seeing the family other than that."

As it was claimed Emwazi had spoken to police and security services three times in a year, it emerged that senior members of the security services could be called to give evidence to the Intelligence and Security Committee about contact between him and MI5.

Sir Menzies Campbell, the former Lib Dem leader who sits on the ISC, said there were "echoes" of the case involving Michael Adebolajo, who was on the radar of security services before he went on to brutally murder Fusilier Lee Rigby with Michael Adebowale.

He told BBC Radio 4: "One of the difficulties here is you can't keep an eye on everyone all the time and, as the committee found in the case of Lee Rigby, there's no doubt that from time to time the security services have got to prioritise those upon whom they're conducting surveillance."

The family of another victim, American journalist Steven Sotloff, said they were "relieved" that Emwazi had been named and now wanted to see him captured and brought to justice.

Video released by the militants last September apparently showed the murder of Mr Sotloff, a 31-year-old freelance reporter for American magazines.

A spokesman for Mr Sotloff's family told the BBC: "We want to sit in a courtroom, watch him sentenced and see him sent to a super-max prison."

Mr Sotloff was last seen in Syria in August 2013, when it is believed he was abducted close to the border with Turkey near the city of Aleppo.

Meanwhile, Cabinet minister and former foreign secretary William Hague insisted a lack of funding was not to blame for the failure of spies to catch Emwazi.

And it was claimed Emwazi's former university was a "hotbed of radicalism" where students "celebrated 9/11".

A picture began to emerge today of Emwazi's background, including the details that:

• He was the son of a mini-cab driver and moved to Britain aged six, having been born in Kuwait
• He has three brothers and sisters and they all lived in a council flat in west London
• He is thought to have attended Quintin Kynaston Academy in St John's Wood, north London, which was also attended by the singer Tulisa
• MI5 apparently persistently tried to recruit him after he graduated from university
• He claims counter-terrorism police arrested him in 2010 and put him on a terror watch list
• This was to stop him leaving Britain but he still managed to flee the country for Syria in 2012

Emwazi complained of harassment at the hands of MI5 agents for more than a year, similar to Michael Adebolajo, one of the two killers of Fusilier Lee Rigby in south-east London in 2013.

The Washington Post reported Emwazi - who has also been known as Muhammad ibn Muazzam - then moved to his native Kuwait and worked in IT, but he was detained by counter-terrorism police in June 2010 upon a return trip to London.

They allegedly fingerprinted him and searched his belongings, and he was not allowed to fly back to Kuwait. Emwazi was put on a terror watch list and banned from leaving the UK.

The FBI said last September that authorities had been trying to identify Jihadi John using various investigative techniques including voice analysis and interviews with former hostages.

Scotland Yard would not confirm the name, and Downing Street declined to comment on the report. Police attended Emwazi's home in Queen's Park earlier today.

One neighbour, who did not wish to be named, described the family as "strange people - not like other people around here".

Another told the London Evening Standard: "They do not mix with us or socialise, or talk to us. Ever since they moved in a while ago they do not say anything to us."

And another local told the Daily Telegraph: "It's a big shock, for me at least I'm a neighbour in this estate, it's a big shock for us"

A spokesman for the International Centre for the Study of Radicalisation at King's College London said: "We believe that the identity and name published by the Washington Post and now in the public realm to be accurate and correct.

"Jihadi John is not special, in the sense that all the foreign fighters have tried to hide their identity by using pseudonyms or literally by masking themselves.

"The fact that Jihadi John has been unveiled in this manner demonstrates that whatever efforts are made, the ability to mask one's identity is limited or in fact impossible, and their true identities will eventually be revealed."

And a University of Westminster spokesman said: "A Mohammed Emwazi left the university six years ago. If these allegations are true, we are shocked and sickened by the news. Our thoughts are with the victims and their families.

"We have students from 150 countries and their safety is of paramount concern. With other universities in London, we are working to implement the Government's Prevent strategy to tackle extremism."

In September, it was revealed Jihadi John was known to MI5 before he travelled to Syria to join Isis. It emerged security officials had identified him but his name and background were being kept secret to avoid jeopardising any hostage rescue missions.

Police and security agents said they also wanted to gather more information before raiding the homes of the fanatic's family and friends.

Abdel-Majed Abdel Bary - a London rapper initially identified as a suspect - was ruled out after analysis of his voice as well as his height and mannerisms.

The 23-year-old came to prominence last year after he posted a photograph of himself on Twitter holding up a severed head.

Other Britons from Portsmouth, Birmingham and Cardiff have been linked to John, who is said to have overseen the torture of hostages and to have led negotiations for French and Italian captives freed in return for ransoms.

It is claimed he was making street collections for genuine Arab charities based in London at the time he came to MI5's attention.

David Cameron has repeatedly called for the infamous terrorist to be punished for his crimes.

In an interview with MailOnline last month, the Prime Minister revealed how he personally watched videos of the brutal beheadings of British hostages carried out by Jihadi John.

"These videos are absolutely horrific and depraved," the Prime Minister said. "And obviously I take the time to see what they are doing so I understand what families have been going through."

Speaking in November, Mr Cameron 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."

- Daily Mail