At least 20 people were detained following a riot in Sichuan on Wednesday sparked by rumours that a man had been beaten to death by traffic policemen, state media reported yesterday. Gan Junyuan , 58, died from a pre-existing medical condition in central Luzhou on Wednesday afternoon, and not because of a scuffle with police, Xinhua reported. Local officials told a press conference yesterday morning that Gan had refused to move his illegally parked truck at around 5.30pm when asked to do so by two auxiliary traffic policemen and had shouted abuse at them. The policemen and Gan jostled each other before Gan became ill and yelled that he needed medicine that he kept in his truck, the report said. Gan's condition worsened after he took the medicine and he was pronounced dead after an ambulance arrived at the scene. The official version of events was essentially in line with a report in this newspaper yesterday quoting a young woman who witnessed the incident. Hundreds of passers-by gathered nearby during the incident and rumours that traffic policemen had beaten Gan to death began to spread rapidly on the internet from about 6pm. Some of those in the crowd overturned seven police vehicles and set fire to two of them. Others hurled stones, bricks and glass bottles at scores of police sent to deal with the rioting. Gan's relatives disputed the official account of events and prevented his body from being removed from the scene as fighting between hundreds of protesters and policemen went on deep into Wednesday night. Local official said Gan's relatives eventually consented to move his body to a nearby funeral home at about 2.30am after hours of negotiations. The crowd was dispersed by about 4am. Police took 20 suspects from the scene, the report said. In June last year another example of violence being prompted by rumours came when thousands of migrant workers attacked and set fire to many police vehicles and the government headquarters in Zengcheng , Guangdong, after hearing rumours that a pregnant migrant woman had been killed by local police assistants. The unrest continued even though widely circulated news reports showed the woman was okay. Hu Xingdou , a Beijing-based commentator, said that because grass-roots government officials and police officers were at the frontline in dealing with conflicts between the authorities and the general public, they would inevitably be targeted by the underprivileged. "When social conflicts meet swiftly spreading rumours, the masses, which have been kept in the dark, may make use of the chance to vent their discontent against society or other phenomena," Hu said.