By Michael Bristow
BBC News, Dujiangyan
The quake claimed at least 270 children at Juyuan Middle School
Parents fear there will not be a proper investigation into why so many schools collapsed in last month's earthquake in China.
Many complain that although local authorities have promised to investigate, they are slow to give out information and worried that contractors and officials responsible for shoddily-built classrooms will not be held accountable.
Their concerns are voiced as China once again promises to investigate the schools issue, according to state-run news agency Xinhua.
Nearly 70,000 people died when the magnitude-8 earthquake struck south-western Sichuan Province on 12 May.
Children paid a heavy price in the disaster, although there is still no overall government figure of how many thousands of school pupils perished in the rubble.
Parents immediately demanded to know why so many school buildings collapsed, and the government initially responded to that call with officials promising within days of the quake to conduct a thorough investigation.
"If quality problems do exist in school buildings, we will deal with the persons responsible strictly," said Han Jin, an education ministry spokesman.
He added that parents who had lost children would get answers, Xinhua reported.
That message was repeated again on Wednesday when the State Council, China's Cabinet, said all collapsed school buildings would be appraised.
But parents whose children died when Juyuan Middle School fell down complain they have been told little about any investigation.
Zhao Deqin's twin 15-year-old daughters died when the school, near the city of Dujiangyan, collapsed killing at least 270 children.
She said: "Officials are not answering questions. They are just playing for time."
Another parent said he had visited the local government offices many times, but had been told only that the "relevant authorities" were investigating.
"The school fell down after 10 seconds. What else do you need to know," he said.
There does appear to have been a problem with the Juyuan Middle School.
US structural engineer Kit Miyamoto inspected the school while he was in Sichuan checking other buildings for clients.
There are early signs of poor construction at Juyuan Middle School
On a website posting, he concluded that the school's concrete floors collapsed because they were not supported properly.
"Just imagine building a Lego house, but using Lego blocks that have no protruding nubs to tie the Legos together," he wrote.
"This Lego house would not be able to resist lateral shaking. The school building is like these weak Lego houses."
An expert from China's Ministry of Construction also came to a similar conclusion, according to China's Southern Weekend newspaper.
He said there were problems with the school's location, structure and with the materials used to build it, it was reported.
But despite the complaints, Juyuan's local authority is saying little.
No-one was available when the BBC asked for an interview with a senior official.
And officials appear to be attempting to tone down public displays of grief and anger.
The school was sealed off earlier this week. Police guard the entrance, preventing people from going in.