HANWANG, China — The official came for Yu Tingyun in his village one evening last week. He asked Mr. Yu to get into his car. He was clutching the contract and a pen. Mr. Yu’s daughter had died in a cascade of concrete and bricks, one of at least 240 students at a high school here who lost their lives in the May 12 earthquake. Mr. Yu became a leader of grieving parents demanding to know if the school, like so many others, had crumbled because of poor construction. The contract had been thrust in Mr. Yu’s face during a...