A vengeful Sichuan farmer killed his doctor in an apparent suicide-bomb attack at a hospital that also claimed the lives of three other people, police said yesterday. Police named only the bomber, Bao Jihou, and his doctor, Li Mingsu, Xinhua said. Thirty-five other people were injured in the blast at Chongqing No 3 People's Hospital on November 14, with five still in critical condition, according to the agency. Police said Bao, 55, of Linshui county, was diagnosed with a detached retina and an operation performed by Li failed to restore his eyesight. 'Dissatisfied with the results of his eye operation, Bao argued with Li and vowed revenge,' Xinhua said. Police said they found evidence in Bao's home linking him to the explosion. In a note left to his family, the farmer said he planned to file a lawsuit against Li 'in the nether world'. The powerful explosion destroyed the entire ophthalmology department on the fifth floor of the hospital. Xinhua said it was the first incident of its type to occur in Chongqing. Media in the southwestern city were prevented from reporting the incident in the days following the explosion. Crimes involving explosives have risen dramatically in recent years. Officials said chemicals used to make explosives were easily available in villages, as they were also used to make fertiliser. Xinhua said Bao used nitramine explosives to blow up the reception area of the ophthalmology department. In March, 108 people were killed in Shijiazhuang, Hebei province, when a jobless man planted several bombs at dormitories belonging to his former employer to seek revenge for perceived grievances. Convicted bomber Jin Ruchao and the woman who sold him the explosives, Hao Fengqin, were later executed.