Germany says it has arrested two former Syrian intelligence officers alleged to have been involved in torturing critics of President Bashar al-Assad.
Both men seem to have sought asylum in Germany after leaving Syria a few years before the migrant influx in 2015.
One them, Anwar R, is suspected of committing crimes against humanity.
He was allegedly in charge of a General Intelligence Directorate (GID) prison where 2,000 people were tortured between April 2011 and September 2012.
The other man, Eyad A, is suspected of aiding and abetting a crime against humanity at the same prison.
A third man – also believed to have been a GID employee – was arrested in France on Tuesday as part of a joint investigation, according to Germany.
The GID is Syria’s most powerful civilian intelligence agency and it has been accused of playing a key role in the violent suppression of the peaceful protests against Mr Assad’s rule that erupted in March 2011.
What are the men accused of?
German federal prosecutors say the two men arrested by police in Berlin and Rhineland-Palatinate state on Tuesday were members of a GID branch in the Damascus area.
They allege that Anwar R, who is 56, was a high-ranking officer who led the branch’s investigative department, and that he assigned and directed operations at a prison where detainees were subjected to “systematic and brutal torture”.
Eyad A, 42, is alleged to have worked for Anwar R’s department.
The prosecutors say that in the summer of 2011 he spent a month at a checkpoint on the outskirts of the capital, where he was tasked with arresting protesters, army deserters and other suspects. About 100 people were taken to Anwar R’s prison each day and tortured there, they add.
Later that year, Eyad A is alleged to have taken part in raids on the homes and hunted down people who took part in protests.
Prosecutors say he assisted in the killing of two unnamed people and the torture of 2,000 prisoners.
Both men appear to have left Syria in 2012, three years before the large influx of migrants to Germany began.
Are there other cases?
German officials say they are investigating dozens of other former Syrian officials under the principle of “universal jurisdiction”, which allows courts to try individuals suspected of committing genocide, crimes against humanity, and war crimes.
Last year, German prosecutors issued an international arrest warrant for Jamil Hassan, the head of Syria’s Air Force Intelligence service, accusing him of overseeing the torture, rape and murder of hundreds of people between 2011 and 2013.
Syria’s government has denied taking political prisoners. It has also denied torturing or killing anyone in custody.
However, UN human rights experts said in a report last March that government forces and affiliated militias were “arbitrarily or unlawfully detaining tens of thousands of individuals in official and makeshift detention centres”.
“They endure various forms of brutal torture and subsist in severely inhumane conditions. Many have died in detention, while others have been summarily executed,” they added.
The bodies of those detainees who have died are rarely returned to their families, who are also not notified about burials, according to the UN experts. As a result, their whereabouts remain unknown.
The Syrian Network for Human Rights (SNHR), a campaign group, said in August that it had documented the deaths of more than 13,600 people due to torture in prisons operated by parties to the war in Syria, with more than 90% occurring in government-run facilities.