A girl plays with her newborn brother at a hospital in Nanjing, Jiangsu province,on Oct 24. 2014. [Photo/VCG]

The case drew nationwide attention after the witness who captured the disturbing scene on camera sent the photograph to writer Chen Lan, who published it on her micro blog, which was reposted 13.6 million times. With the help of some people who offered clues, Nanjing railway police found Duan within 24 hours.

Duan now faces criminal charges, and the judicial process is expected to begin soon. And we hope the case will set a precedent for child abuse cases, so as to deter tens of thousands of potential child abusers from turning their evil ideas into practice.

Many may wonder whether there are "tens of thousands" of potential child abusers in the country. The number of potential child abusers is likely to be much higher considering the estimate of Wang Dawei, a professor at People's Public Security University of China, that only one out of seven such cases is reported to police.

Worse, according to the 2016 annual report of Girl Protection, a branch of China Foundation of Culture and Art for Children, the average age of child abuse victims has been decreasing. Of the 778 victims whose ages were made available last year, 125, or 16 percent, were below 7.

These cold numbers show how serious a social problem of child abuse is and how important it is to provide greater protection to children against child abusers. Punishing child abusers for their crime could be a good beginning in this direction.

On June 1, International Children's Day, the Supreme People's Court said that quite a high percentage of child abusers are people who are known to the victims: Relatives, family friends, even family members. That corroborates the report of Girl Protection, which said about 70 percent of child abuses are committed by people who have close relations with the family. Uncovering such cases is much more difficult, because many young children don't know what has happened to them. And even if they, after reaching a certain age, realize they were sexually abused, they might not speak about it, if the abuser was somebody who they trusted.

Apart from the judiciary acting tough against child abusers, the authorities have to improve sex education for children. Children should also be taught how to identify potential abusers and protect themselves from such people. And, most importantly, they should be taught to say "no" and call the police when someone tries to harm them.

The author is a writer with China Daily. zhangzhouxiang@chinadaily.com.cn