• Twitterer amoiist caught up in police blog probe
• Inquiry centres on murder ‘libel’ against officials

The hundreds following amoiist on Twitter were used to his stream of messages. But they ended abruptly with two terse updates early yesterday morning.

“i have been arrested by Mawei police, SOS” he wrote. Then shortly afterwards: “Pls help me, I grasp the phone during police sleep.”

His followers quickly passed on his plea to other Twitterers. But since then there has been silence from amoiist – also known as Peter Guo, or Guo Bofeng – who is apparently the latest internet user to be caught up in an inquiry that began with claims of defamation but which police now say involves “state secrecy issues”.

As many as seven bloggers have been detained over claims that a 25-year-old woman, Yan Xiaoling, had been gang-raped and murdered. It was further alleged that the man responsible was connected to local authorities in her city in Fujian province, southern China.

Officials dismissed the stories, which first surfaced in late June, and insisted Yan had suffered a haemorrhage caused by an ectopic pregnancy. They turned their attention to tracking down those they suspected were responsible for the stories.

According to Global Voices Online, Guo posted an interview with Yan’s mother in which she repeated the claims and accused local authorities of a cover-up.

An employee at Mawei police station told the Guardian: “These cases are in the process of investigation. We are not in charge of the case so we can’t tell you more. We will release information if there is progress.”

The case is testament both to the growing ability of Chinese citizens to share information through the internet, and to the restrictions on those who do.

In a recent, unpublished interview with the Guardian over the government’s Green Dam censorship programme, Guo said: “The significance of internet in China is huge. It can’t change the current situation in China right away, but it has deeply influenced China. Through the internet, Chinese society has become more and more diverse, and more importantly many people who are unaware of the truth have started to hear different voices.”

Guo, who described himself on Twitter as “a trouble maker in Amoy [Xiamen], living with character sales”, is reportedly a professional interpreter. His two calls for help were in English, although he generally uses Chinese.

He often blogs and tweets about news, current affairs and internet censorship, frequently with a satirical tinge, and has more than 1,500 Twitter followers. A message posted several hours before his pleas read: “Peter Guo, one of the twitterers in China, originally from the Fujian countryside, not a famous blogger; people called him amoiist, good character, young, handsome.”

Liu Xiaoyuan, who represents another detained blogger, You Jingyou, said lawyers had been told they could not meet their clients because the case involved “state secrets”.

Liu’s client wrote his power of attorney in advance because he feared he might be the next to be detained. Another man who was away when police visited his home yesterday told Liu he believed they planned to detain him.

The lawyer said: “I do not know why exactly [You] was detained. Whether it is because he wrote something or he spread something or planned something is still unknown. But from the police we know it was connected to the Yan Xiaoling case.”

He said bloggers had been held more frequently in the last two years. “I think it is because the internet’s power is getting bigger and bigger and the internet uncovers many issues so the authorities get more pressure.”

Another lawyer told the Xinkuaibao newspaper that if officials had been libelled they should sue the bloggers involved rather than launching a criminal case. “We can tell that the local officials haven’t caught up with the need for the development of open information and the internet. They have not adapted to it and feel it is a big deal if some bad information appears on the net.”

Twitter is blocked in China but many on the mainland still tweet through a variety of means.