Residents say children as young as 12 have been recruited by child labor rings, equipped with fake identification cards, and transported hundreds of miles across the country to booming coastal cities, where they work 12-hour shifts to produce much of the world’s toys, clothes and electronics.

“Last year I had 30 students. This year there are only 14. All the others went outside to find work,” said Ji Ke Xiaoming, 35, a primary school teacher whose students in Erwu Village are mostly ages 12 to 14. “You know, we are very poor. Some families can’t even afford a bag of salt.”

China is now investigating whether hundreds, perhaps thousands, of poor children of the Yi ethnic minority group in Liangshan were lured or even kidnapped to work in factories that are increasingly desperate for the kind of cheap labor that powered China to prosperity over the past two decades.