Madrid: A Spanish court said on Monday it would investigate a criminal complaint against members of the Syrian security and intelligence forces related to alleged state terrorism and forced disappearance of people.

The complaint was brought by a Syrian-born woman of Spanish nationality who says her brother disappeared after being arrested and was tortured and executed in 2013 at a centre in Damascus under the control of the Syrian security forces.

It is the first criminal case against Syrian security forces to be investigated by a foreign court, said Toby Cadman, a lawyer for London-based chambers Guernica 37 which is representing the woman bringing the charge.

Other cases have been filed in Germany and France, but have not yet been accepted by the courts, he said.

Although there would be formidable obstacles to bringing the Syrian security force members named in the complaint before a judge in Spain, Cadman said there was still an acceptable chance of them standing trial.

The woman identified the body of her brother from a cache of more than 50,000 images taken and smuggled out of the country by a Syrian forensic officer who defected from his position and fled Syria, Guernica 37 said.

Spanish High Court judge Eloy Velasco has asked Syrian authorities to notify eight members of the intelligence and security services that they must appoint legal representation in Spain ahead of any case, the court said on Monday.

Under Spanish law, the examining magistrate investigates accusations brought in a criminal complaint before moving into a trial phase.

The woman behind the case and the forensic officer have been summoned to appear before the court on April 10 for questioning, the court said. Three other witnesses will appear in court for questioning on May 9.

The top U.N. human rights official called on March 14 for tens of thousands of detainees in Syria to be released and for torturers and executioners to be brought to justice as part of a lasting agreement to end its civil war.

Syria’s government and President Bashar al-Assad routinely deny using torture or extrajudicial killings and have dismissed the accusations of the defector who smuggled out the images as a fabrication.

(Reporting by Sonya Dowsett; editing by Mark Heinrich)