Button Murder Case

Under the dark, damp and dirty bridge tunnel, a beggar found that where he usually lived, there was a naked female corpse crawling with rats. The female corpse was still exuding the fragrance of sesame oil, but she was holding a red button in her hand... In the tea house, the female teacher Li Yazhen, who had failed to court, suddenly went crazy and forced the travel reporter Jian Dongping to take off his coat and return to him a red button she had sewn on his shirt. As a result, after getting the button, Li Yazhen was strangled in front of her own home that night... Collector Wang Sheng died of illness and left a will, leaving all his collections to Qiu Yuan, an industrialist who also belonged to the collectors club, but Qiu Yuan received 10 empty boxes... Who is the female corpse under the bridge? Why was she holding a red button when she died? What does her death have to do with the Collectors Club? What do those buttons mean? Is it a simple prank? Or does it indicate that a living life is coming to an end? Who is the murderer? In repeated confrontations with the five suspects, Jian Dongping finally found the murderer's flaw. As the murderer said, this is not so much a reasoning game as a psychological duel. Everyone has weaknesses and everyone may do something wrong. Guess who the murderer is?