Cox's Bazar, Bangladesh (CNN) In the middle of the night in a town in south-eastern Bangladesh, a Rohingya boy is found bound and blindfolded and dumped in the marketplace. He is pale and skinny, but he is alive. And nearly four months after he went missing, that is enough for his parents.

In April, Mohammad Faisal vanished from Kutapalong refugee camp in Cox's Bazar, Bangladesh where he lived with his family. His parents feared their boy, aged about 13, had been trafficked onto a fishing vessel, or perhaps worse.

CNN - Stolen son: The child traffickers preying on the Rohingya