By bizn_fun 
The documentary followed the account of ‘Didi’, a Chinese man who said he left home after being promised a well-paid job, but was trafficked into Cambodia and forced to work inside the walled compound.
Didi said he was made to work from 20:00 to 08:00 local time (13:00 to 01:00 GMT), targeting victims in Europe and the United States, and was not permitted to leave the complex.
He also shared secretly recorded footage with the BBC and the Global Anti-Scam Organisation (Gaso), a volunteer-run group that helps rescue and support trafficked victims.
In a video diary recorded inside his dormitory, Didi said he was told to “keep scamming as long as you’re alive”, and that he’d witnessed another victim being beaten and dragged out of the office after making a mistake.
In desperation, Didi attempted to escape by jumping from the third floor. He later took shelter in a safe house in Phnom Penh, before eventually returning to China.
Three years after the documentary was broadcast, he is now working in a factory in southern China.
The investigation also featured testimony from another Chinese man, Mi Lijun, who said he became seriously ill while being held at the compound. He was found abandoned on a highway and taken to hospital. The BBC obtained footage of his final hours before he died from organ failure.