The development of the case is unexpected and the details are winning. Since Beauty Zhang reminded me to pay attention to the details at the beginning, I was highly concentrated on the details and reasoning about the development of the case from the beginning to the end of the movie. As the saying goes, "Since ancient times, deep love cannot be retained, but only a ruse can win the hearts of the people", so at the beginning, I also wondered whether the development of this case would also be a ruse. However, in order to avoid being set up, I always remind myself to think against the set up. When the scene where Fu Jian goes to knock on the door to find Chen Jing appeared (I don't think the date appeared at that time), coupled with the discovery of the body at the riverbank in the morning of April 13 (the deceased was identified as Fu Jian based on the fingerprints at the riverbank scene and the missing person from the guesthouse), I began to speculate that the suspects were in the form of Chen Jing and Chen Xiaoxin (Chen Jing's daughter - a middle schooler), as well as Shi Hong, the math teacher (a mathematical genius, who I think is the smartest person in the drama). When I learned that Tang Chuan (an associate professor in the Criminal Police Academy, a genius like Shi Hong, good at investigation, deduction, math, and psychology) and Shi Hong knew each other, and when Shi Hong pretended in front of the police that he didn't know Chen well, I began to conclude that the suspect had to be one of them, and that either Shi Hong had killed Fu Jian in order to protect Chen and the girls, or Chen or Chen's daughter killed Fu Jian, or Chen and her daughter killed Fu Jian together, or Chen and her daughter together killed Fu Jian. Either Chen and Shi Hong killed Fu Jian together. However, when I learned that the deaths of the riverbank victims and the destruction of their bodies required a person of greater strength to do so, I first ruled out the possibility that Chen Xiaoxin had committed the crime alone. And because, on the night of April 12, Chen Jing and Chen Xiaoxin both have an alibi (the body was found on the morning of the 13th, according to the body of the deceased can be deduced that the time of death should be the night of the 12th), objectively I can only exclude them, but in fact, I feel that it is not quite right in my heart, but I can't find a reason for it. In this way, the only suspect left is Ishihiro.
The development of the movie plot, from Tang Chuan's description of Shi Hong's character and the dialog exchanges between the two geniuses, I ruled out the possibility of Shi Hong being the real murderer, and thought that Shi Hong was most likely creating all sorts of evidence to cover for the real murderer, and because of Shi Hong's adoration for Chen Jing's, Chen Jing returned to the object of my suspicion. Also, because the police hinted that Shi Hong, Julia Chen may be with another man (Kun), deliberately stimulate Shi Hong, so that Shi Hong revealed his foot, I was guessing, Shi Hong will do, is deliberately go along with what the police think, more conducive to let the police think that he is the murderer, or ignore it. When I saw that Shi Hong went to follow Kun after hearing the police's hints, I knew that it was the first approach; when I saw that Shi Hong sent a threatening letter to Chen Jing, that Shi Hong stole the sonic instrument out of the house, and that he threatened Chen Jing himself that he was going to hurt Chen Xiaoxin, but that Chen Xiaoxin wasn't hurt; and in fact, drove close to Tang Chuan, I guessed that Shi Hong didn't really want to kill Tang Chuan. As a matter of fact, I wondered if Shi Hong really became psychologically twisted from the moment he knew that Jing Chen was interacting with Gon, but Tang Chuan's conversation with Shi Hong, where Shi Hong said that what he wanted was not to walk out, but to walk on, coupled with the moment when Chen Xiaoxin wasn't hurt, I was certain in my heart that Shi Hong was creating an illusion to make everyone think that he was a psychopathic tracker and a murderer --In order to protect Chen and the others (it was already revealed in the movie at that time that it was Chen and Chen Xiaoxin who killed Fu Jian together), he wouldn't really want to kill Tang Chuan, partly because of his own character and partly because of the deep friendship he had with Tang Chuan. At the end of the movie, even though it was already known that it was Julia Chen and Chen Xiaoxin who killed Fu Jian, I still couldn't figure out how they had an alibi and yet killed Fu Jian, and what happened to the bodies by the riverbank. Later, Tang Chuan revealed that Fu Jian was indeed killed by Chen Jing and Chen Xiaoxin, but the time was the evening of April 11, and the dead man by the river was Shi Hong in order to have time to create an alibi for Chen Jing and the others, and deliberately postponed the death of Fu Jian (the dead man by the river) to the evening of April 12, which coincided with the discovery of the body on the morning of April 13, so that from the beginning of the story, it was not clear how they had an alibi for the murder of Fu Jian. The body was found on the morning of April 13, so that from the very beginning we (including the police) were misled into thinking that Fu Jian died on the evening of April 12th. In reality, however, the dead man by the riverbank was someone else, a false impression deliberately created by Shi Hong to make people think that the dead man was Fu Jian. The ending of the movie seems to be what I expected, but not what I expected. I guessed that Shi Hong would succeed in "taking the blame", but I didn't guess that Shi Hong would actually kill someone, in order to cover up the fact that Chen Jing had killed someone; at the same time, I didn't guess that Chen Jing would choose to turn herself in when she learned of what Shi Hong had done for herself and her daughter. (Note that at this point, all the evidence has already pointed to Shi Hong, and there is no longer any conclusive evidence that can prove that Julia Chen and her daughter killed Fu Jian. In other words, Julia Chen is completely exempt from any criminal responsibility.)