WUFU, China (CNN) -- The first thing you notice about this small town in China's quake-devastated Sichuan province is that every building is standing except one: the primary school.
Bi Kaiwei rushed to his daughter's school, digging with his hands, desparately trying to find her.
As many as 200 children were killed here, crushed to death when three stories of concrete came crashing down.
At the school gates, some parents have left their children's identifications cards as a sort of makeshift memorial. Others still cling to them, like Bi Kaiwei.
When the major earthquake struck a week ago, Bi came rushing from the nearby factory where he worked and started digging with his bare hands.
"We tried to save as many children as we could," Bi said, still holding his daughter's school ID photo. "But these concrete slabs were too heavy, we couldn't move them."
Five hours later, he found the body of his little girl, Yuexin, near the building's only exit.
"They were so innocent," he said.
Standing next to him, his wife, Liu Xiaoying, held another photo of Yuexin. The 13-year-old girl, sporting a long ponytail and a red-and-white-striped shirt, smiles broadly in the photo as she holds the brim of her red cap between two fingers. Watch a report from Wufu's devastated school »
"The scene was like a slaughterhouse," Liu said between tears. Her husband, with his arm around her, looked away at the rubble of the school behind them.
"The children were in piles, they were all bodies."
A few miles away, a government building stands virtually untouched by last Monday's massive temblor.
Bi and his wife are among a group of parents who believe their children were killed by a building made of cheap, shoddy materials that rendered the school a virtual death trap.
"If this was a decent building, my daughter wouldn't have died," said Li Yan, holding a handful of dusty rubble.
Thin, bendable wire is the only evidence of rebar, the material that holds concrete structures together. Generally speaking, the less steel in a concrete building, the less strength it has to withstand movement.
Brian Tucker, a seismologist with the California nonprofit Geohazards International, said a civil engineer in China told him that the country has no centralized, uniform code for earthquake-resistant public buildings such as schools or hospitals. The size of the fallen beams and columns pictured in video of the disaster appear inadequate to the task, he said.
"Some of the columns that are broken have exposed rebar that is not tied together essentially with horizontal bands, which makes sure the rebar stays attached to each other and to the concrete," Tucker said.
Reginald DesRoches, a civil engineering professor at the Georgia Institute of Technology in Atlanta, said the collapse of schools was surprising, since they typically are built to tougher standards.
But he said many of the buildings that fell were built before 1976, when an earthquake that killed 250,000 people spurred Chinese authorities to require earthquake-resistant construction for many buildings.
According to China's state-run media, government officials have promised to find out why nearly 7,000 school buildings collapsed during last Monday's earthquake, which measured between 7.9 and 8.0 in magnitude.
A spokesman for the Chinese Embassy in Washington said Friday that, based on what he has heard, the quality of construction in the earthquake zone exceeded the nation's building standards for southwestern China, given the strength of the hit.
However, Wang Baodong added that "relevant investigations will be conducted at the appropriate time."
Wrenching scenes of survivors being dug out of collapsed schools and apartments after the May 12 earthquake suggest widespread disregard for building codes in the rapidly urbanizing region, according to several civil engineers who spoke to CNN.
Unlike a 1999 earthquake in Turkey, where allegations of widespread corruption in the country's building industry followed an earthquake that killed nearly 20,000 people, one British engineer said nothing he's seen of the Chinese disaster suggests corruption.
"But it would suggest that the people who've actually built these buildings, maybe paid for them, haven't been able to afford the highest standards, the best materials, the latest designs," said Tom Foulkes, the director-general of Britain's Institute of Civil Engineers.
The quake also damaged a major dam near the city of Dujiangyan, but an investigation revealed that the dam is stable and safe, China's state-run news agency Xinhua reported last week.
Foulkes said China's major dams are well-designed.
"I think the real danger will be from hundreds, maybe thousands, of smaller dams, some of them possibly very ancient, which have never experienced this sort of shock before," he said.
Tucker, with California-based Geohazards International, said China's earthquake danger zones are "very diffused," compared with the United States, where fault zones tend to run in narrow bands.
"The growth in some of these cities is so fast, it would be no mean feat to keep up with it," he said.
He said school safety was a special concern of his organization. California authorities have closely monitored the construction of schools since a 1933 earthquake in Long Beach killed more than 100 people, many struck by falling debris as they ran out of shaking buildings. Earthquake-resistant buildings there cost about 4 percent more to design and build than other structures, he said.
"It's not rocket science, but it is something that needs some attention," he said.