Secrets Cannot Be Told

A bizarre murder occurred in City S. At first, I thought it was a suicide, but the forensic autopsy report could not change my mind. The door of the room at the crime scene was closed, and there were no signs of a fight in the house. However, the cause of death turned out to be a sudden heart attack, and the deceased's family had no history of heart disease. During the autopsy, the forensic doctor found a small fleshy ball protruding from the heart of the deceased, which resembled a woman's face. This made everyone look at each other and couldn't help but think of an accidental death case that occurred a year ago. The deceased also died of a sudden heart attack at that time. The forensic autopsy found that his heart also had a small meat ball that looked like a woman protruding. Although the scene was messy, because the deceased had a history of heart disease, the police concluded the case as accidental death. Although one was a murder case and the other was an accidental death, the protruding fleshy ball in the heart that resembled a woman attracted the attention of police officer Ye Yehao, who immediately applied to investigate the case and classified the two cases as a serial murder case. However, it was discovered that a suicide case two years ago was related to this case. When the case came to a dead end, another murder case appeared. After an autopsy of the same sudden heart attack, it was found that a fleshy ball resembling a woman's face was protruding from the heart. What hidden things are there that have not yet been discovered? What is right and wrong behind the death?