Mystery surrounds the identity of a blogger whose postings about sexual exploits with Shanghai women has sparked controversy. The writer, called Chinabounder on the Sex and Shanghai blog, claimed to be a British teacher in the city.

His lurid accounts of his life outside of the classroom led Zhang Jiehai, a professor of psychology at the Shanghai Academy of Social Sciences, to launch a campaign to track down the author and expel him from the country.

In an essay written on his own Chinese-language blog, Zhang labelled the author a "foreign scoundrel" and attracted numerous postings, some violently worded, in support of his campaign.

News agencies have now reported that when an e-mail was sent to a contact address on the Sex and Shanghai site, a person repsonded to say the author was actually a group of performance artists.

It went on to add that that they made up the stories to investigate online vigilante behavior, and that the writers included a British man, an Australian woman, two Chinese men and a Japanese woman.

The message said the blog had since been closed to ensure the safety and well-being of the group's Chinese members and ordinary expatriates in Shanghai.

But Zhang told China Daily he still believed the blog was a true account of one foreigner's life in Shanghai.

"I hope the blogger could come out and apologize to the public or someone identify him and kick him out of his teaching post," said Zhang.

He tried to distance himself from numerous readers' postings on his blog that called in aggresive terms for a manhunt.s.

Zhang had previously encouraged "netizens and patriots" to investigate the people and the places mentioned in the blog, but is now taking a more considered approach.

"I stated clearly at the beginning that what the man did does not violate any law," said Zhang.

"He is just immoral. And such an immoral person is not qualified to be a teacher.

"But I also don't want this to turn into violence.I welcome any tip on the identity of the blogger, but I don't want people to trace him and do something violent.

"In Chinabounder's blog, the author described himself as "lacking in moral fibre, but coping with the situation.

"The blog's traffic reportedly surged from 500 hits to more than 17,000 in the course of a few days before it was closed.

In a posting made after Zhang launched his campaign, Chinabounder condemned the criticism,claiming many expats and local men were no different from him.

South African Jeremy Goldkorn, editor of Beijing- based Danwei.org, a website about media and urban life in China, said he believed the blogger was authentic.

He said he thought Chinabounder was trying to cover his own back after becoming shocked by the recent publicity.

"If it was performance artists, then they would be seeking real publicity now as they have got what they wanted," said Goldkom."If you write something like this then it always comes back to haunt you, eventually.

"People may think you can write anonymously,but you always leave footprints on the Internet, especially when you are writing about other people.

"While I think there has been an overreaction by professor Zhang and other people, this person had it coming in a way.

"If you are going to write things like that on the Internet, then people are going to get offended.

"It does highlight an issue of Westerners being decadent not just in China but in other East Asian countries."