Siddhartha Dhar new Jihadi John
A masked man points a weapon as he speaks in this still image from a handout video obtained on January 4, 2016 from a social media website which has not been independently verified. Britain was examining the Islamic State video showing a young boy in military fatigues and an older masked militant who both spoke with British accents.Reuters

The Islamic State jihadist with a British-accent who was seen threatening the United Kingdom in the latest Isis propaganda video is believed to be Indian-origin Siddhartha Dhar, a Hindu man who converted to Islam and adopted the name Abu Rumaysah. 

The Isis video released on Sunday showed the execution of five men that the group accused of being British spies, and a masked man who shot one of the hostages threatened terror attacks in the UK. 

Even as voice recognition experts are analysing the video, reports suggest that the man is thought to be Dhar, who had been arrested in Britain in 2014 on suspicion of encouraging terrorism but escaped after he was released on bail. 

Dhar is said to have fled to Syria in 2014 and he had posted a picture of him on Twitter posing with an AK-47 rifle and his new born baby.

"A lot of people think it is him," a source told BBC

Dhar's own family is said to have identified the voice of the masked jihadist claiming like it "did sound like him", according to The Telegraph

"I believed the audio to resemble, from what I remember, the voice of my brother but having viewed the short clip in detail, I wasn't entirely convinced which put me at ease," the Isis jihadist's sister told BBC. 

Dhar was born to a Hindu family that had migrated to London from India and had converted to Islam when he was 19.

Last year, the British man dubbed as 'Jihadi John' who carried out several beheadings and appeared as the main executioner in Isis videos was identified as 26-year-old Kuwait-born Mohammed Emwazi using voice recognition. He was said to have been killed in an airstrike in November. 

The new masked man seen in the recent Isis video has now been attributed the moniker 'Jihadi John'. 

 A phonetics expert who checked the new Isis video told The Huffington Post that the man had an accent similar to Emwazi, but appeared to have been speaking English for longer than the former Jihadi John.

Jane Setter, professor of phonetics at the University of Reading, also said that some features of the Isis fighter's accent were similar to those in 'Indian English'. 

The young boy who was also seen in the Isis video speaking in a British accent has also reportedly been identified as the son of London's 'jihadi bride' Khadijah who fled to Syria some years ago. 

The boy, believed to be only four years old, was seen in the ten-minute video saying - "We are going to go kill the kafir [non-believers] over there."