Family of teen learned of his death in Syria on Facebook
Abdullah Deghayes, 18, whose uncle is a former Guantánamo detainee, is believed to have died earlier this month but little is known about the circumstances, his father Abubaker Deghayes confirmed, as he said he is considering retracing his son's footsteps to try and find answers.
They only found out about his death on Monday after a photograph was posted Facebook and had no idea that he was in Syria, believing that he had gone to Libya, where he has relatives, after running away in January.
"At the moment we do not have details of his death. All that we know is that he was killed in Syria. The family is mourning,” he said from his home in Brighton, East Sussex
"We are all in mourning. I'm trying to find out what's happened. At the moment we don't have any details. We found out on Facebook.
"I hope he died for a noble cause, trying to help Syria. I need to find out. I might go and travel to see.
"He was a youngster who didn't communicate a lot. With parents, once they grow, they don't tell you much about their lives."
Mr Deghayes said his son, who was due to go to university in Brighton, lived in the seaside city with his mother and had left the UK in January.
The teenager is the nephew of Omar Deghayes, who was held by the United States as an enemy combatant at Guantánamo Bay detention camp between 2002 and 2007 after he was arrested in Pakistan.
Omar, who is currently in Tripoli, said he knew very little of the circumstances of his nephew's death and had only heard one eyewitness account of what happened.
He said: "He ran away from his home ... we didn't know at first."
His friends have also expressed surprise at his death, saying they too thought he was in Libya and he had never expressed a desire to join the rebel forces.
The Foreign Office said they were looking into the death, whilst police are supporting his family.
Around 400 Britons are believed to have gone to Syria over the last two years, authorities believe, with an estimated 20 having died.
Counter-terrorism investigators have expressed concern in recent months about aspiring British jihadis travelling to the country and becoming radicalised.
In January alone, 16 people were arrested on suspicion of terrorism offences related to Syria compared with 24 arrests in the whole of last year.
MI5 director-general Andrew Parker told MPs last year that the civil war has been a magnet for hundreds of British nationals looking for the opportunity for "jihadi" activity, many of whom have come into contact with al Qaeda-supporting groups before returning to the UK. It is believed around 250 of the 400 who went to Syria have now returned.
Tributes to the Abdullah have been posted on social media sites.
One man, Nezar El-bayouk posted on Twitter: "R.I.P. To My Boy Abdullah Deghayes. Jannah InshAllah!"
Another friend Miss' Newland, posted: "R. I. P this is such a shock, can not get my head around it. Everyone's gonna miss you Abdullah Deghayes. much love xxx"
His Facebook site states that he was studying at the University of Brighton, had attended Longhill High School in Brighton and that he worked for adidas.