XUZHOU, China — In front of a van plastered with pictures of about 100 children's faces, Xiao Zhaohua and Wu Xinghu pleaded with passersby for help.
"Please don't think this is someone else's problem, and never take your eyes off your children!" they shouted. "We don't want more people to feel the same sadness we do."
Xiao, 37, and Wu, 33, are on a personal mission to find their abducted children. The faces on the van are of other missing children — and cases of children being snatched are continuing unabated in China despite a recent police crackdown.
In downtown Xuzhou, a major city in Jiangsu Province on China's eastern coast, Xiao and Wu stopped their van and placed a cassette deck on the road. The song that emanated described the pain felt by parents of abducted children.
The lyrics included: "You are my whole life. However bitter it may be and whatever perilous mountains and rivers I have to cross, I'll keep looking for you until I die."
Xiao knows this anguish all too well. His life was turned on its head at about 7 p.m. on Feb. 14, 2007, when his 5-year-old son, Xiao Xiaosong, vanished while going to buy candy at a nearby store with his older sister.
"I gave Xiaosong some money to buy sweets because he said he was hungry, but he disappeared before his sister realized what had happened," Xiao said. "I should have gone with them to the store."
Xiao, who ran a clothing store in Huizhou, Guangdong Province, at the time, is still torn by guilt, and blames himself for letting his children go unaccompanied.
Xiao reported his son's disappearance to police, and also took matters into his own hands. He shut down his store and distributed flyers seeking help to find Xiaosong. He drove around the province on his motorbike to spread word of his plight.
He joined an association of families of abducted children that was established by a scholar in Beijing devoted to resolving the abductions.
In 2011, Xiao squeezed out his last savings to purchase the van for 50,000 yuan (about $8,000). With the help of supporters, other parents of abducted children joined him on trips to all corners of China to seek clues that might help trace their missing kids.
Chinese police have not released official statistics on the number of abductions. But according to police sources in Guangdong Province, the figure could reach nearly 10,000 per year throughout China.
Human trafficking rings are believed to be involved in many of these abductions, the sources said, adding that the going "trafficking rates" are 100,000 to 160,000 yuan for a boy and 60,000 to 100,000 yuan for a girl.
According to the sources, most of those abducted are boys, who are mostly sold to buyers in farming regions where males are viewed as superior and boys are the preferred heirs.
The trafficking reflects the fact that many families with no children or with only a daughter under China's one-child policy tend to want boys, according to informed sources.
At some railway stations in urban areas, migrant workers from rural areas reportedly can be seen making a sinister sales pitch to passersby. "Won't you buy a boy?" they ask.
Some children have been sold to crime syndicates, where they are beaten and fed drugs. Some are reportedly forced into prostitution or to commit burglaries.
The Chinese government established a program in April for reining in human trafficking. This comes after a police crackdown from 2009 to 2012 uncovered about 11,000 human trafficking rings across China. More than 54,000 children were rescued.
Xiao said none of the 7,000 children whose parents are members of the association were rescued during the crackdown. But Xiao refuses to give up hope that his son will be found.
"My boy may not have given up hope that he will be saved, so I'll never give up trying to find him," he said. "I believe he'll come back one day, so I'll keep up my search."