Now a court in Germany will give its verdict in the case of a man accused of presiding over systematic mass torture and killing of those detained there. Anwar Raslan, 58, is charged with crimes against humanity in the Damascus jail known as "Hell on Earth".

The trial in Koblenz is the world's first criminal case brought over state-led torture in Syria. At the heart of it is a man alleged to have been a high-ranking security service officer under President Bashar al-Assad as mass anti-government protests were violently crushed in 2011.

Many protesters and others suspected of opposing the regime were rounded up and detained in the Al-Khatib facility in Damascus where, prosecutors say, Mr Raslan directed operations. Charging him with 58 murders and rape and sexual assault, they accuse him of the torture of at least 4,000 people held there between 2011 and 2012.

Anwar Raslan was arrested in Germany in 2019, having successfully sought asylum here. He denies all the charges against him, says he had nothing to do with prisoners' mistreatment, and says he tried to help some detainees.

 His trial is extraordinary for several reasons. It is unprecedented in taking on Syria's state-led torture, and it was prompted by the arrival in Germany of hundreds of thousands of Syrians who'd fled their own country.

Many of the almost 800,000 Syrians who now live in Germany brought with them terrible stories of what happened to those who opposed the Assad regime. German human rights lawyers took up their cause, using the principle of universal jurisdiction to bring the case to court. This allows serious crimes committed in one country to be tried elsewhere.

Wolfgang Kaleck, head of the European Centre for Constitutional and Human Rights, which has led the case, says it's hard to talk about justice given that hundreds of thousands of people have been tortured and tens of thousands of people have died as a result.

But perhaps most notably, the trial has given a voice to those whom the Assad regime tried to silence. Fifty survivors have given evidence to the court in Koblenz; 24 are co-plaintiffs in the case.