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 Security Directorate (GSD) prison where at least 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 GSD employee – was arrested in France on Tuesday as part of a joint investigation, according to Germany.
The Syrian government has denied killing or mistreating detainees.
The GSD is Syria’s most powerful civilian intelligence agency and it has always played an important role in quelling internal dissent.
Western powers have accused GSD commanders of helping to oversee the Assad government’s violent suppression of the pro-democracy protests that erupted in Syria in March 2011.
German federal prosecutors say the two men arrested by police in Berlin and Rhineland-Palatinate state on Tuesday were members of a GSD branch in the Damascus area.
They allege that Anwar R, who is 56, led the branch’s investigation department and that it operated a prison where detainees were routinely subjected to torture and physical ill-treatment.
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 helped round up people who took part in protests suppressed by security forces.
Prosecutors say he assisted in the killing of two people and the torture of at least 2,000 prisoners.
Both men appear to have left Syria in 2012, three years before the large influx of migrants to Germany began.
German officials say they are investigating dozens of other former Syrian officials, who are also accused of human rights abuses.