"It was about 3 am. We were all in a deep sleep. I didn't wake up and realize what had happened until I had already been carried out of the house. When I cried loudly, they threatened me with a gun," Ye said.

After being taken, he was transferred from person to person and transported in trains and cars before arriving at a village in Fujian province, where he was sold to a family.

"The trafficker lied to my adoptive parents and said that I was his own child. He pretended to be sad, saying he was reluctant to make the deal. They bought me for 10,000 yuan ($1,480)," he said.

Losing Ye was a huge blow to Liang and his wife.

"Telecommunications were underdeveloped at the time. We got the bad news several days later from a telegram my mother sent me and we rushed home immediately," Liang said.

The three men who took Ye were arrested a week after his abduction, but they did not know the boy's whereabouts as they had already sold him on to other traffickers.

"Every year, when our family had dinner together on the eve of Chinese New Year, we would put a bowl of rice and a pair of chopsticks on the table, hoping our son would come back," Liang said.

In his quest to find Ye, Liang moved around the country, taking work in Zhejiang and Jiangsu provinces, as well as Shanghai. He estimated he spent more than 100,000 yuan looking for his son.

"We didn't give up. We always believed we would find him one day," he said.

According to official statistics, 756 child-trafficking cases were cracked in China in 2015. From 2013 to 2016, Chinese courts concluded 3,713 criminal cases involving the trafficking of women and children.