Dossier concerning Zheng Xinchen (鄭信臣), a male native of Chaozhou, Guangdong (廣東潮州), whose death in Shanghai in September 1944 was investigated as suicide by poisoning. The police death report gives his age as 35, describes him as having no fixed residence and no occupation, and records the place of death as Room 2 of the Youfa Hotel (有發旅館), Lane 54, Yongping Street (永平街五四弄). He was found dead there on 24 September 1944.

The police investigation reconstructed Zheng's movements before his death and collected testimony from the hotel staff and from his wife, Zheng Xiaoshi (鄭蕭氏). The investigative narrative states that Zheng had previously worked in Nanjing and had taken a room at the Youfa Hotel shortly before his death. When hotel personnel entered the room, they found him already dead. No remaining poison container or other obvious poisonous substance was found in the room.

Particularly important is the survival of two handwritten letters treated as evidence in the case. One is addressed to his wife and contains language consistent with a farewell, urging her not to remain bound by him and to continue with her life; another is addressed to acquaintances. The evidence envelope explicitly records two letters (信二件). The dossier concludes with a formal medico-legal examination. The forensic record documents the body systematically and gives the cause of death as 服毒身死—death resulting from ingestion of poison.