MUMBAI: The latest Islamic State video shows the militant group executing five men accused of being spies. Nothing out of the ordinary in that statement, as ISIS (or Daesh) have released several propaganda videos showing executions.

The key takeaway in this video, however, is the militant carrying out the executions. A masked militant featured in the video is believed to be Briton Siddhartha Dhar, also known as Abu Rumaysah -- a father-of-four from Walthamstow in east London. Dhar had previously been held on suspicion of encouraging terrorism as he was linked to the Al Muhajiroun group, but later released after which he travelled to Syria to join the militant group.

Dhar’s sister has identified his voice in the video. "A lot of people think it is him," an official source told the BBC, as Dhar seems to be set to replace masked militant Mohammed Emwazi, dubbed Jihadi John, who was reportedly killed in a drone strike in Al-Raqqah, Syria on 12 November 2015. Emwazi had become symbolic of the group as he featured in a large number of Daesh videos, speaking in a marked British accent.

Dhar has become the focus of international media given his journey from bouncy castle salesman to Islamic State militant. As the Daily Mail reports, “Hindu-born Londoner Siddhartha Dhar, 32, was known as 'Sid' to friends and enjoyed drinking, would take girls to his favourite action movies and dreamed of being an NHS dentist… Dhar's family say he was a 'sensitive boy' who 'changed' as a teenager after the death of his father and converted to Islam, shunning TV and music, sleeping on the floor and even telling his mother he couldn't love her anymore because she is not a Muslim. He stopped studying and rented bouncy castles for children's parties while supporting banned militant group Al-Muhajiroun and running 'roadshows' aimed at attracting troubled youngsters in inner-cities.”

(A photo of Dhar).

(A photo of Dhar playing with his child, who is seen clutching the handgun, in an image taken once he had moved to Syria).

(Dhar discussed his former bouncy castle rental business in a VICE documentary in June 2013, his job while supporting banned groups and marching for Sharia law in Britain before he fled while on bail. Courtesy The Daily Mail).

After Dhar’s arrest last year for encouraging terrorism he was forced to hand in his passport and put on a terror watchlist, but managed to escape to Syria when out on bail, taking his pregnant wife and four children with him.

Dhar then wrote ISIS' 46-page guide to life in the caliphate promising a holiday lifestyle with home comforts, projecting life in the Caliphate to that of a 'plush Mediterranean resort' with British chocolate like “Kit Kats, Bounty bars and Snickers freely available 'and the best lattes and cappuccinos around.”

His 46-page guide to the Islamic State covers everything from weather, food and transport to education, people and technology. The book’s cover has a picture is ISIS troops firing at Jerusalem as they march on the Israeli city, with his name credited with al-Britani in the end, a suffix used by militants to indicate that they are from Britain.

“If you were worried about leaving behind your local Costa coffee then you will be happy to know that the caliphate serves some of the best lattes and cappuccinos around,” he writes.

“'This really depends on where you are, but as it stands the caliphate offers an exquisite Mediterranean climate that has all the makings of a plush holiday resort,” he says of the country’s weather.

“There are no classes promoting homosexuality, evolution, music, drama, interfaith and the rest of the rubbish taught in non-Muslim schools. Your child's delicate mind is well and truly protected in the caliphate,” he says.

'If you thought London or New York was cosmopolitan then wait until you step foot in the Islamic State,' he writes.

The Daily Mail quotes Dhar’s sister, Konika Dhar, saying that 'I am going to kill him' if it's found he is the new Jihadi John. She has previously described how her brother was a typical teenage boy known to friends as 'Sid' who enjoyed football, blockbuster films, dating girls and drinking Baileys to mark special occasions. He also had a passion for rock bands Nirvana and Linkin Park.

The publication spoke to Dhar’s school friend 'an incredibly quiet boy who never ever got into trouble'. She said:”'He had a few friends but was pretty much a loner, never one of the popular kind of boys. He had hardly any confidence and was pretty much forgettable. It seems to me he's only become this type of person for attention.”

When Dhar’s father died when he was 16, he decided to drop out of school and took up a number of varied jobs -- working at Boots and later as a Bouncy Castle salesman.

According to the Daily Mail, Siddhartha's former neighbours in Walthamstow, north east London, suggested his wife may have helped radicalise him and others. He met wife Aisha when she was 23, and the couple have five children, including one called Usama, named after Osama bin Laden.