The fall of Bashar al-Assad's regime did not free all Syrian prisoners.
China's prison houses more than 5,000 detainees in the northeast of the country, which is under Kurdish control.
These prisoners, including some Britons, are suspected of being fighters and supporters of the so-called Islamic State. Most of them are said to have been loyal to her until her last stand in 2019.
Orla Guerin, the BBC's chief international correspondent, was given the rare opportunity to visit the prison.
