A 46-year-old female teacher surnamed Liu died inexplicably after hosting an online course for her students in Xinzheng city, Central China's Henan province, on Oct 26. Video clips posted online by her daughter show Liu being abused by strangers who hacked into her online class, something her daughter believes led to her death.

The local police are probing the case. Their investigation will conclude if online violence caused Liu's death. It will also throw more light on a new phenomenon in which people hack into online classrooms to abuse teachers and students. This has become increasingly common and those who do it even boast of their "experience" in WeChat groups. Liu is not the only victim, many other teachers and students have been subjected to the same.

This kind of behavior is no harmless joke, but a crime considering that the legal rights of students and teachers get violated. Those who hijacked Liu's online class certainly deserve punishment if it is confirmed that their action caused her death.

The latest document introduced by the Cyberspace Administration of China requires websites to establish mechanisms to check online violence. One way is through a button allowing a teacher to stop anyone other than him or her from chatting in the classroom, or even kicking out illegal participants from online classrooms.

However, solving just one case is not enough. Behind all these violations is a cybercrime chain of hackers who hack into online classrooms and obtain passwords which they sell for a price. Only by cutting that illegal chain can this illegal activity be contained.

Let classrooms, offline or online, belong to teachers and students alone.