With the fall of the last bastion of the self-proclaimed Islamic State (IS, formerly ISIS/ISIL) near the Syrian town of Baghouz, the United States has demanded European countries take back and put on trial hundreds of foreign fighters captured by the US-led coalition. The father of two young German men who travelled to Syria to join IS in 2014 opened up about his years-long quest to reunite with his sons, in an interview at his home in the town of Zierenberg, near Kassel, on Monday. He called on the German government to allow for their return.

The last time real-estate manager Joachim Gerhard saw his two sons, Fabian and Manuel (born in 1992 and 1996), was shortly before they secretly left for Syria at the end of October 2014. The two brothers had converted to Islam in April and May 2014.

More than four years later, at the end of February, Gerhard received a phone call from an unknown number saying that the eldest son, Fabian, was alive and a prisoner of the Free Syrian Army. "No one was asking for money. It was merely information that three days earlier Fabian had been imprisoned together with 20 more people," Gerhard said before adding that the detention centre was supposedly located in the area of al-Qamishli, near the Syria-Turkey border.

In March 2015, just a few weeks after Gerhard had travelled to Turkey in the hope of meeting up with his sons across the border in Syria, he received a message announcing they had died in Kobane. Fabian and Manuel have never been declared officially dead by any official German authority, according to their father who also refused to believe they are gone.

Gerhard's living room is covered with photos of his two sons, some portraying them in Syria: one depicts Fabian, the oldest, standing with black headgear against the backdrop of a lake. His left index finger points towards heaven, a symbol of IS militants, while he wears a rifle around his upper body.

Gerhard never stopped hoping and gathering evidence to prove that his two children were still alive. More than 20 trips to Turkey and one trip to Syria, contacts with smugglers and informants have increased hope, he said. "In 2017 I spoke with a representative of the LKA [Landeskriminalamt, German law enforcement agency]. This person confirmed to me that both my sons were still alive and living in Raqqa, before the offensive [US coalition intervention]," Gerhard said.

The rooms of the two brothers have remained unchanged. Manuel's room showcases computer books, a collection of hats and an electric guitar. Photos of Julia, Fabian's wife, are still in his room. She too had converted to Islam and was part of the brothers' plan to go to Syria, Gerhard said, but she ended up not leaving with them.

Fabian wanted to become an actor, Manuel a photographer. They both moved to Berlin for their studies, and once they returned to live with their father in Kassel they were introduced by a friend to Islam.

During the spring of 2014, Fabian told his father that he wanted to live according to the Islamic faith and some months later, his younger brother followed suit. Visits to the mosque in Kassel became more frequent until the decision, kept hidden from Gerhard, to leave.

"In our family there had never been strong political discussions. Not one of us is a member of a political party or ever supported war," said Gerhard.

The young men's radicalisation happened in only three months, Gerhard recounted. "They always said that it had nothing to do with IS and with joining the war in Syria, they always said that they had embraced Islam in order to be able to live better. Things changed a bit two weeks before they left: they didn't listen to the radio anymore, no music, they wouldn't come to eat in a normal restaurant. But the fact that they were planning to leave, none of us would have predicted it."

Gerhard teared up when recalling how both sons left behind a goodbye letter saying "thank you for being good parents." "They asked to trust them, that this was their faith and their way, which they had to follow."

The news of Fabian's supposed imprisonment comes at a time when the status upon return of foreign fighters is being debated by policymakers around the world.


More videos