Age of responsibility

"When a case is serious enough to constitute a public menace, the police have an obligation to investigate and give the public an answer. But it's the court's job to judge whether the girl is too young to avoid criminal responsibility. We cannot fail to act simply because of her age," said Li.

She noted that similar cases have occurred in other countries, including Japan, the United Kingdom and the United States.

Although official statistics are unavailable, experts claim that China has seen a marked rise in juvenile delinquency since 1990, and that the number of cases involving assailants below the minimum age for criminal charges is rising. However, the question of how society should deal with "problem" children and prevent them from committing further crimes is one many countries face.

"I know that some countries have experienced cases of this type and we can learn from the way they handled them," said Li, recalling a trip she made to the UK in 2010 to study procedures for juvenile offenders.

"Britain has a special law that aims at intervention, not simply punishment, of minors. It clearly states the "punishment" for juvenile offenders between the ages of 7 and 18," she said.

Although cases in the UK are tried by a juvenile court, the sentence handed down doesn't punish the child. Instead the parents are compelled to attend government-funded "parenting classes" where they learn how to raise and educate their children correctly.

"Britain also has the Children Act. For children with a marked tendency to hurt others or display signs of abnormal behavior, community social workers formulate a 'safety correction and track plan', which usually lasts around three years," said Li.

Xinyuan's grandmother and sister look at photos of the toddler.

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