A jihadist who fled Manchester for Syria has been identified as a key member of a clique of British fighters that include the notorious Islamic State extremist Mohammed Emwazi, it has been reported.

Raymond Matimba is believed to have left Britain in 2014 to link up with terrorists in the region. According to the Daily Telegraph, he went on to join a group of high-profile British jihadists that included Emwazi, the executioner also known as Jihadi John. The newspaper also reports that Matimba had links to the Manchester suicide bomber Salman Abedi.

Zimbabwean-born Matimba, who adopted the nom de guerre Abu Qaqa al-Britani al-Afro, is said to have become a leading sniper for Isis. The 28-year-old spent time in Raqqa, Isis’s de facto capital, and reportedly may still be alive.

The newspaper published a video apparently showing Matimba, Emwazi and Britons Reyaad Khan and Junaid Hussain in a coffee shop in the city in 2014. The men are lounging on sofas, their weapons leaning against the wall, while they charge their phones. The clip, filmed in secret by an infiltrator, is said to be the first to show all four together.

The video’s source, whom the newspaper did not identify, told the publication Matimba had urged the terror cell to organise an attack on his home city of Manchester, and had spoken to Salman Abedi in the months before his attack in May. The source said: “He said [to the group] that he hated his city, that he wanted it to be bombed.”

Matimba was reported to have been killed this year, however his mother, Moncia, 60, told the newspaper that she had not received any official confirmation.

“I am still going through hell and I never expected such a thing like this to happen in my life,” she said. The support worker last heard from her son in 2015 via WhatsApp. “I contacted the counter-terrorism authorities,” she said. “I said I don’t want to talk to him any more. Eventually I changed my number.”

Emwazi was killed in a 2015 drone strike after becoming one of the top targets for the US-led coalition fighting Isis. The Kuwaiti-born Londoner appeared in a number the group’s videos, including those in which he is shown murdering American reporter Steven Sotloff and British aid workers David Haines and Alan Henning.

Emwazi was suspected of having been part of a four-member Islamist terror cell known as The Beatles because of their British accents.

Hussain, a computer hacker, was described as a key Isis operative before he was killed by a US drone strike on 24 August 2015. The 21-year-old, from Birmingham, was said to have been number three on the Pentagon’s “kill list” of Isis targets.

Khan, from Cardiff, is thought to have travelled to fight in Syria late in 2013 and appeared in the group’s propaganda videos. He died when a car he was travelling in through Raqqa was targeted by an RAF remotely piloted aircraft.

This year a Guardian investigation found that 16 convicted or dead terrorists had lived within a 2.5-mile radius of a Moss Side address that was the childhood home of Ronald Fiddler, also known as Jamal al-Harith, who died in a suicide attack near the Iraqi city of Mosul in late February. One of those people was Matimba.

After the Manchester arena attack, police confirmed they were investigating bomber Abedi’s links with Raphael Hostey, who was killed in an airstrike in Mosul last April aged 24. Hostey, also known as Abu Qaqa al-Britani, is believed to have sponsored hundreds of terror recruits, including Matimba, Fiddler and Muslim convert and former RAF gunner Stephen Gray.