More than 10,000 villagers in Chongqing clashed with police after the local government failed to deal with a school murder case, officials and human rights group said yesterday. At least four people were arrested and more than 10 injured when 200 armed police were sent by the Youyang county government to disperse protesters who had gathered outside the county government office building on Friday, the Hong Kong-based Information Centre for Human Rights and Democracy said. The group and local media said a court police car was destroyed by angry protesters. Both the county government office and police bureau confirmed the riot yesterday, but refused to give more details. 'We solved the problem already as police intervened ... and we have passed the [school murder] case to the local court,' a spokesman from the county's propaganda office said. The riot was triggered by the stabbing of Form One student Dong Zhegui by classmate Liu Yu during a quarrel at the Zhongdu Middle School on Thursday, the Youyang Daily newspaper said. Youyang resident Chen Jun , who writes a weblog, said the school sent only Dong to hospital 40 minutes after the attack, and the delay in treatment proved fatal. 'It was very sad that none of the school staff took any action to save the poor boy and let him bleed, and left the knife in his stomach for more than half an hour,' Mr Chen wrote on his blog. 'It is also unbelievable that police even stopped Dong's mother from entering the school gate to see her son.' The newspaper reported that Liu and three other students were taken away by police for questioning, but all were released soon afterwards because they were too young to be charged. Dong's relatives were unhappy about the lack of action, and more than 30 of them blocked the main gate of the school at 5am on Friday, the newspaper said. They later went to the county government office to seek help. A video provided by Mr Chen showed Dong's mother lying on the ground at the school, and a large crowd gathering outside the county government office to confront armed police. Mr Chen said Dong's case had won the sympathy of thousands of onlookers, swelling the size of the crowd. Local media said the protest had seriously affected the county government's operations because all the main entrances to the building were obstructed. The county government said it had spared no effort to calm the crowd, but the reports gave no details. It was the second mass riot in Chongqing in a month. On June 3, a crowd of more than 10,000 people confronted police after city inspectors beat a pair of flower sellers, one of whom died.