Copenhagen (AFP) – Denmark’s Supreme Court on Tuesday is to rule in a case of a Danish citizen of Syrian origin who claims time he spent with the Islamic State (IS) group was as an agent for Danish intelligence.

If that assertion is upheld, Ahmed Samsam could seek to overturn a 2018 conviction he received in Spain for belonging to IS, a jihadist group that tried to carve out territory in Syria and elsewhere.

“A positive ruling from the Supreme Court would enable him, among other things, to apply for a retrial of the criminal case that was decided in Spain,” Samsam’s layer Rene Offerson told AFP.

But complicating the matter is the position of Denmark’s intelligence services, which refuse to confirm or deny the identity of their informers for security reasons.

Samsam, who was handed an eight-year sentence by the Madrid court that convicted him, served most of his time in prison in Denmark, after being transferred. He was released in 2023.

He denies any terrorist activity, saying that his membership of the IS, during trips to Syria in 2013 and 2014, was done for the Danish Security and Intelligence Service (DSIS) and, later, the Danish Defence Intelligence Service (DDIS).

That claim has been backed by several testimonies and journalistic investigations presented to a lower Danish court that tried to establish whether or not he was a Danish intelligence agent.

“As far as I can see, there would be no major complications for the intelligence services if the Supreme Court ruled in Ahmed Samsam’s favour,” Offerson said.

“This would simply mean that the intelligence services would have to confirm that Ahmed Samsam was an agent, which everyone knows he was.”

But Frederik Waage, a law professor at the University of Southern Denmark, said such an acknowledgement “would be a sensation”.

“It would interfere with the operations of the Danish intelligence agencies in a way not seen before in Danish law,” he said.

He stressed the importance to the intelligence services of keeping their sources anonymous – but said that such arguments were weakened in this case, given “it has long been a public secret that Samsam was an agent”.

Apart from the IS charge, Samsam faces other legal problems. On Monday, Copenhagen’s court of appeals upheld a three-month sentence against him for violence against a law enforcement officer.