The tip-off came from one of his followers. Kevin, a netizen who fights against child molestation and pornography, received information that a man in Harbin, Northeast China's Heilongjiang Province, was suspected of molesting children who he recruited to model children's clothes.
Kevin found photos of the man, surnamed Li, kissing several boys on his social media accounts. He quickly contacted the operators of the social media platform and alerted local police.
One hour later, all of Li's social media accounts were suspended. Three days later, Li was detained by Harbin police after an initial investigation.
Li's case is not an isolated one. Many child pornography and molestation websites remain online, and illegally producing and selling child pornography videos and photos has become a lucrative business in China. Some people make profits through charging membership fees for visiting the websites.
There are no statistics available on how many children are forced to be involved in pornography. But according to estimates from the International Labor Organization, about 1.2 million children worldwide are involved in child porn every year, with many falling prey to pedophile organizations.
Underground network
Another social media group nicknamed "unique beautiful children's voices" was exposed on China's Twitter-like Weibo, charging "333 yuan ($52.90) per month for a junior VIP visiting membership, 666 yuan for intermediate membership and 999 yuan for senior membership".
After paying 50 yuan, members could watch photos and video clips of children taking off their clothes and touching themselves.
In its VIP group, screen shots obtained by the Xinhua Daily Telegraph reporter showed several members watching videos on live streaming sites, and the group also organized offline trade in child pornography videos. Through visiting the group's online chat records, the reporter saw an advertisement that billed 2,000 yuan for molesting a boy. The group had a total of 1,927 members and its owners made money mainly through live broadcasting as well as online and offline trading.
Zhengzhou police in Central China's Henan Province last August arrested the owner of an online forum who shot and uploaded photos and videos of naked girls. The videos contained images of them in different poses and adults molesting them.
The underground child pornography industry seems to have led to an increase in sexual assault offences against the underage in China. An intermediate court in South China recently tried a case involving a 24-year-old man accused of raping a primary school girl he met on Tencent's instant messaging service QQ. The man asked to meet the girl in person after watching pornographic videos of young girls. The judge said that defendants in most rape cases involving juveniles had watched pornographic videos before committing crimes.
Difficult to bust
Kevin, who has 770,000 followers on Weibo, said he receives hundreds of reports from fans each month. He exposes illegal online forums and Weibo accounts of suspected pedophiles, and reports them to Weibo platform operators and the police.
But not each report leads to an arrest, as "the suspects are good at skirting regulations, and it's difficult to investigate and hunt down suspects in the outlying cross-border areas," said Kevin.
Owners of some child pornography websites also switch servers to avoid being caught, and some deliberately set up servers overseas, he said.
To crack down on the underground porn business, Zheng Ziyin, a lawyer specializing in child protection, said that police should punish both the operators of the social media platforms and the managers of the pornographic websites, and at the same time, work with other law enforcement departments in cyber-security administration, children and women protection to jointly crack down upon children molestation offences.
