The father of two British teenagers killed fighting for Islamists in Syria has told of his “great shock” at losing a third son in a stabbing.

Abdul Deghayes from Brighton died in the early hours of Sunday morning after he was attacked in a car that had crashed, Sussex Police said.

The 22-year-old was found just before 9.30pm on Saturday in the passenger seat of a silver Volkswagen Polo, which had crashed into other cars.

He had a “number of stab wounds” and died from his injuries at the Royal Sussex County Hospital in the city, a force spokesman said.

Speaking to Press Association, his father Abubaker Deghayes said: “As a family we are in mourning. It is a great shock.

“Adul was very popular with his friends. He loved Brighton a lot. He was a cheerful guy.

“We just know he was found in a car, there was a lot of blood and he was brought to hospital.

“They tried to keep him alive and he died in the morning. I don’t know exactly what happened. We are still waiting for more information.

“I can’t even think of who would take such a step to do this to Adbul.”

Abdul – who was jailed in 2017 for drug dealing – is the twin brother of Abdullah who was killed fighting in Syria in 2016 aged 18.

Their brother Jaffar, 17, was killed in 2014 while trying to overthrow Bashar Al-Assad’s government.

They are survived by fourth brother, Amer, a former finance student, who also travelled to Syria where he is understood to be continuing to fight the cause.

Speaking to Press Association from Syria, he said he did not want to discuss his brother’s death but described him as someone who “stood up for the weak”.

Elm Grove, where the attack took place, remained cordoned off on Sunday afternoon.

A large team of forensics investigators wearing white suits arrived on the scene and have been inspecting the road leading up to a row of cars and as well as searching underneath vehicles.

Fire crews have also arrived and have started to search drains.

Chief Inspector Andy Bennett appealed for witnesses to come forward and

said: “We are trying to establish the exact circumstances of what has led to this young man’s tragic death.

“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.”

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

There was “no recognition” 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.

After the review their uncle Omar Deghayes – who was arrested in Pakistan in 2002 and spent five years in Guantanamo Bay – hit out at police claiming they took “no action whatsoever” while his radicalised young nephews were being racially abused.

The report also revealed the family had been the subject of racial abuse for more than a decade – with Omar’s detention thought to be a factor.

The publicity around his release appeared to have sparked a persistent and prolonged campaign of racial hatred, according to the report.

It said they were targeted by organised right wing groups and at one point the message “Behead all Muslims” was daubed in 12 inch-high letters near their former home in Saltdean near Brighton.

Asked if police are considering whether the attack on Abdul was racially motivated, a spokesman said: “At this stage of the investigation there is nothing to suggest that this is a hate crime but we are keeping an open mind at this time.”