There have been calls for one of the most wanted French jihadists to be extradited to France following reports that he is being held by Kurdish forces in Syria.

Thomas Barnouin, 36, is said to have been among a group of French nationals who were detained on December 17 by the Syrian Kurdish YPG militia. He is believed to be a key member of a militant network to have developed in the southwestern Toulouse region.

“Several French (nationals) were arrested in northern Syria in the Hassakeh area, near the Iraqi border,” a source close to the matter told French news channel LCI. Two other Frenchmen picked up at the same time have been named as Romain Garnier – a former swimming champion – and Thomas Collange.

The three men are said to have converted to Islam around the turn of the century. Barnouin – who subsequently called himself “Abdelhakim” – was later sentenced to five years in prison for running an extremist recruitment network in southwestern France. French intelligence lost track of him after his release, when he headed for Syria with his wife and children – according to French media.

Barnouin is said to have been close to Mohamed Merah, a gunman who killed seven people – including three Jewish children – in the Toulouse area in 2012. The 23-year-old petty criminal was shot dead by police after a 30-hour siege.

Extradition call

On Wednesday a lawyer representing Latifa Ibn Ziaten, the mother of one of Merah’s victims, said she would seek Barnouin’s extradition to France. “It’s before French justice that he should answer for his acts, before the families and victims of these attacks committed both as planner or accomplice,” Samia Maktouf told BFMTV.

It’s thought that an extradition could help French authorities understand more of the events surrounding the radicalization of Mohamed Merah, whose brother was sentenced to 20 years in jail in November for association with a terrorist group.

Imad Ibn Ziaten was one of three soldiers shot dead by Mohamed Merah, who also gunned down an eight-year-old girl among his victims outside a Jewish school in Toulouse.

Originally from the town of Albi, Thomas Barnouin is also believed to have been close to two men known as the Clain brothers, one of whom claimed responsibility for the Paris attacks of November 2015 on behalf of the so-called Islamist State.

Barnouin, Merah, the Clain brothers and others are said to have come under the influence of Olivier Corel, a French national originally from Syria known as the “White emir” of Artigat, his base close to the foothills of the Pyrenees. The 69-year-old, believed to be the driving force behind the Salafist movement in the region, was recently thought to be in Syria.

Domestic threat

An arrest warrant is reported to have been issued in France for Barnouin, although it is unclear whether wanted jihadists caught in Iraq and Syria will be returned to their home country.

ISIL’s loss of territory has brought intelligence warnings that French militants may return to France and continue to plan attacks. Earlier this month France’s foreign minister estimated the number of French jihadists still in the region at about 500.