Police have arrested a man on suspicion of murdering the brother of two British teenagers killed while fighting for Islamists in Syria.

Abdul Deghayes died early on Sunday in his home town of Brighton in East Sussex, police confirmed.

The 22-year-old was found just before 9.30pm on Saturday in the passenger seat of a silver Volkswagen Polo that had collided with other vehicles, police said.

They arrested a 26-year-old local man who handed himself in to a Brighton police station yesterday afternoon.

Police said he was “believed to have been present at the time of the incident”.

Deghayes had a number of stab wounds and died from his injuries at Royal Sussex County hospital. Elm Grove, the site of the incident, remained cordoned off.

Ch Insp Andy Bennett of Sussex police appealed for witnesses. “We are trying to establish the exact circumstances of what has led to this young man’s tragic death,” he said.

“We are aware the car was in collision with other vehicles shortly before he was found to have suffered these injuries, which we are satisfied were caused maliciously and not as a result of the collision. We have made one arrest, but we are seeking to trace others who we think may have been involved,” he added.

Deghayes, who was jailed in 2017 for drug dealing, is the twin brother of Abdullah Deghayes, who was killed fighting in Syria in 2016, aged 18. Their brother Jaffar, 17, was killed in 2014 while fighting with forces attempting to overthrow Bashar al-Assad’s government.

Speaking at the time of Jaffar’s death, their father, Abubaker Deghayes, said his grief “cannot be described”. He claimed the government was criminalising young Britons who had travelled to the war-torn country.

A serious case review published in 2017 found professionals had missed opportunities to prevent the two teenage British Muslims being radicalised before they travelled to fight in Syria.

There was no recognition that Abdullah, Jaffar and their three siblings were becoming vulnerable to radicalisation in Brighton, the report said.

There was also little understanding of the part religion played in the lives of Abdullah and Jaffar, who were believed to have been with the al-Qaida-affiliated al-Nusra Front when they died, the review added.

A third brother, Amer Deghayes, a former finance student, also travelled to Syria to join efforts to overthrow Assad and is understood to still be fighting for the cause.

