Niu Guozheng hails from Henan, a province of inland China. Employed in the law enforcement agency of the Pingdingshan prefecture, whose economy is largely based on mining - an activity he has portrayed in two distinct photographic series - Niu witnessed situations that his own sense of justice considered as unjustifiable. He documented living conditions in centres for custody and interrogation (in Chinese 'shoushensuo'), thinking that the treatment of the prisoners was not worthy of his country's ethics. His activity as a camera-carrying policeman, accepted or tolerated by his colleagues and by the inmates, was motivated by his belief that only knowledge of facts can bring about the solution of problems. The centres for custody and interrogation were shut in 1997 thanks to a reform of the criminal justice process. Exhibited at the Central Academy of Fine Arts in Beijing for a short time, Niu Guozheng's reportage has not been published to date. His images, stark and disturbing in some cases, tenderly poetic in others, characterise an eye that merges the documentary intent with a very strong aesthetic sensibility which reminds us of the classic masters of photography.Text in English, Chinese, and Italian.