The teacher, who was detained by police on May 17, is alleged to have raped the students after summoning them into his office to inspect and revise their homework. Most of the girls were allegedly raped multiple times.

The online appeal, signed by the 'parents of eight schoolgirl victims', said: 'Since the parents reported the case [in mid May], aside from some brief questions asked when police brought the students to hospital for a check-up, police and prosecutors have not sent anyone to the victims' families to investigate. Nor have any local education officials come to ask us about this.

'From the conversations that one regional headmaster subsequently had with some of the parents, asking us to keep this low-key, we are worried that, without media intervention, this case will be treated coldly and the criminal suspect will not be punished as he should be under law.'

The letter's drafter, a father whose 10-year-old daughter was allegedly raped at least three times, spoke yesterday to the South China Morning Post, which is not releasing his name, to protect his daughter's identity.

'Whenever she hears people talking about this, she still cries and cries,' the 34-year-old father said. 'She often just stares aimlessly for a long time; and she is hardly eating.

'Her school performance has slipped a great deal. She used to be No 3 in the whole district; now she doesn't want to go to school.'

The father said his family discovered what happened after his niece told her mother that she wanted to be transferred to a different school. Upon the mother's questioning, the girl said she had been raped multiple times over the past year and a half. The girl's grandad then spoke with his other granddaughter and discovered she had a similar account of sexual abuse at the teacher's hands.

The angry father, a migrant worker, said all of the girls allegedly raped were 'left-behind children', meaning they stayed behind in the countryside with relatives when their parents moved to cities for work.

He said he was worried that, in the month since he returned home, officials still appeared apathetic over the case.

It was only yesterday, he said, after the letter had started circulating online, that the local police delivered to his home an investigation report dated June 8 and saying that traces of semen were found on the bed in the teacher's office, but it offered no conclusion.

He said an education official called him yesterday and offered him 20,000 yuan (HK$24,500), but he refused it.

'We are not doing this only for money. We want to go through the courts. We want justice for our daughters,' he said.

Reached by phone yesterday, Zhulian village chief Zhao Yuexi told the Post that he didn't have details about the case.

A county police officer admitted that his team was investigating the case, but he offered no additional information.