On Wednesday a netizen posted a message on Reddit.com, an expat forum, that he had worked with and known Robinson for five years, but by Friday, the netizen had removed the message.

Beijing Youth Daily reported that Robinson had been identified by former students on Facebook.

Other netizens said that the case highlighted how the background checking process in China's international schools should be tightened.

"Chinese employers, please do background checks before hiring international staff members," said netizen Fo Yue Da Xiong, on Sina Weibo, China's Twitter-like service.

International schools in Beijing hire teachers from their native countries and through Chinese agencies.

An education counselor with the international program at a high school attached to Tsinghua University, who declined to give her name, said that Chinese agencies often do not carry out background checks.

"Schools make phone calls or write to people for references to check prospective teachers' credentials," she said, adding that it was often difficult for schools to do criminal background checks.

"If applicants are from the United States, we can ask them to show a criminal background check by the US government. But it's hard to do that in China," she added.