Within a period of about a month, nine students had gone missing from a special education school in Hohhot, capital city of China's northern Inner Mongolia Autonomous Region.

"I was shocked at that moment. Recently, quite a number of hearing and speech impaired people were found to be missing. I rushed to the school to look for the students."

"They had taken with them all their valid certificates, including their ID cards and certificates of disability. It seemed they had long prepared for their departure."

But where had the students all gone? Why had they secretly left without informing their parents or school administrators? Did they leave of their own will or did someone force them?

Stay tuned to "Frontline" for the story of "Salvage from the Edge of A Cliff " right here on China Radio International.