Moses Malek has said on Twitter he has joined ISIS. Malek was detained in 2013 in his home country, where he claimed to have fought with members of Al Qaeda. He told the Daily Mail his father knew nothing of his intentions.

Since his arrest, there has been no mention of Malek on IS propaganda video. He was reportedly killed in combat in April 2014.

It is not clear where Malek became radicalised.

At 13, Malek started attending a radical Islamic faith school in Belgium. His parents first suspected something sinister when their teenage son started showing interest in the Muslim faith.

His mother said her son would say things like: “Don’t drink alcohol”, “It’s not a good thing to have faith in the devil” – and “All Christians are bad and I’m going to take over the world”.

She was later arrested for her alleged involvement in giving the teenager alcohol.

But she maintained that she did not know where her son was from or who he was. Prosecutors have now been accused by Belgian prosecutors of trying to frame him.

“We think that the trial, which will take place in a few months, might help to discredit the judge”, Professor Jochem de Bruyn, a sociologist from Brussels University told the DPA news agency.

But the head of the Islamic Society in Belgium, Wouter Preeke, insisted this has had absolutely no impact on the case. “We never would ask him about his nationality or parents’ religion,” he said.