Shen Mingyu and Han Sicheng returned to the door of the laboratory, Han Sicheng received information from the forensic personnel and the forensic doctor, the DNA extracted by the forensic doctor from the charred corpse was compared, and Wang Xiaomeng was the same, and it was basically determined that the deceased was Wang Xiaomeng, and the investigators found a particularly fierce fire in the fifth laboratory, inferring that this was the source of fire, leaving a small section of unburned circuit boards and charred dry batteries around, because most of the fifth laboratory were flammable and explosive chemicals, so everything else was almost burned.

In the Rui Yi case, the forensic personnel extracted shoe prints that did not belong to Rui Yi at the scene, and the shoe size was the same as that of Liu Qiwei's case, which was 37 sizes.

At this time, the three people who were attending classes in Building A also came to the laboratory accompanied by the police, and when they learned that Rui Yi and Wang Xiaomeng were killed, they were all stunned.

Zhang Muru couldn't hold back her tears and cried on the side. And Ning Lin's face changed suddenly, and she was very panicked, because according to the threatening letter, it would be her turn soon.

Although Wen Qiao looks calm on the surface, her face can also be described as extremely bad. Han Sicheng asked the female police officer on the side to comfort everyone, and asked: "Students, I know your mood now, I'm not afraid to tell the truth, if you don't catch the murderer one day, then you will be in danger at any time, I'm not alarmist, so I need your cooperation." The three girls nodded and looked at Shen Mingyu.

Shen Mingyu understood that they could only rely on himself now, and he asked the girls to tell them what happened from going to class to after class today.

First of all, Zhang Muru, she took a criminal law class on the top floor of Building A, the criminal law class is three consecutive classes, Zhang Muru went to the corridor to eat breakfast in the middle of the big class, because the eggs she bought tasted bigger, so she hid in the corner and ate, and ate for about 10 minutes, and she never went out in the classroom since then.

Then there is Ning Lin, she is in class on the 2nd floor of Building A, she went to the toilet because of a stomachache during recess, because there are too many people, she didn't return to the classroom until she was ready for class.

The last is Wen Qiao, she is in class on the 3rd floor, and she happened to go to call during the recess, because she agreed to talk to her mother on the phone last night, but it was canceled because of an emergency, so she wanted to take advantage of the big class break to make a call, and when she came back, it was almost class.

The police officers stationed in Building A and Han Sicheng did not see anyone leaving Building A. Shen Mingyu felt the need to go to Building A to have a look, so he asked the police to send the three girls back to the dormitory, and he and Han Sicheng went to Building A.

When he came to Building A, Shen Mingyu found that the classroom here was similar to Building B, but the direction and layout were different, and when he walked to the third floor, he was surprised by the scene in front of him.

"We seem to have missed a very important point......," he said, gesturing to the corridor connecting Buildings A and B.

Han Sicheng also suddenly realized,

"That's right, we were really dizzy by this case, and we actually ignored this, if you go to Building B from here, not only do you not have to go downstairs, but the speed is also relatively fast, the three of them don't have a clear alibi, and there is a large flow of students between classes, no one will pay attention if you run casually, the murderer must have taken advantage of this." At this time, the technical department called and told them that Rui Yi's mobile phone had been unlocked, and there was an anonymous message in it, which was to ask Rui Yi to meet in the toilet.

"No wonder she walked so fast at the time, so many cases happened, her emotions have reached the extreme, she was afraid that she would not go to the next one and it would be her turn, but she didn't know, even if she went to the next one, it was herself, and the murderer used people's hearts to have a set, and the other is the problem of shoe prints, I have investigated their shoe sizes before, only the dead Wang Xiaomeng is size 37, the murderer is likely to wear shoes that are not suitable for his feet to commit the crime, and the rest of the people are shoes smaller than size 37, And shoes with a large shoe size are not very good for walking and doing things, and the murderer is estimated to have adapted to it for a while in advance. Shen Mingyu concluded.

"You seem to have forgotten someone." Han Sicheng reminded.

"That's right, I forgot to ask Wen Qiao's shoe size before, do you doubt her, we were all at the express station when Liu Qiwei died."

"Xiao Shen, what we need in this line of work is to be rigorous, not to let go of any detail, and not to miss the details because of personal emotions." Only then did Shen Mingyu react, because he was mixed with personal emotions, which almost affected the detection of the case, so he apologized to Han Sicheng, and after speaking, Shen Mingyu sent a message to ask Wen Qiao's shoe size, Wen Qian not only answered, but also sent Shen Mingyu the purchase record of many pairs of his shoes.

Shen Mingyu said:

"Wen Qiao is a size 38.5 shoe, and it is estimated that he can't walk in size 37." Han Sicheng nodded, and the two of them were going back to the abandoned dormitory to see the situation first.

On the way back to the dormitory, Han Sicheng received another call from the forensic staff, who said that the components of the things found at the fire source point of the fifth laboratory had been detected, and it seemed to be a simple timed ignition device.

When Shen Mingyu heard the news, he suddenly realized,

"I see, I know how to kill two people in different places at the same time." They came to the corridor of Building 7 and brought their colleagues together to exchange information, and Shen Mingyu began to analyze at this time: "I already basically know what the situation of these two cases happened today, first of all, we first focused on Wang Xiaomeng's case, the forensic personnel said that a similar timed small ignition device was found near the fire point, this device can automatically ignite after a few hours, thus causing a fire house, the murderer is a person who is very familiar with Wang Xiaomeng's life and rest, and also knows her habits, this modus operandi is very simple, I asked the teacher who managed the laboratory, the key to the fifth laboratory is only the teacher and Wang Xiaomeng, and Wang Xiaomeng has a habit, she will throw the key on the table at will when she returns to the dormitory, if she doesn't go to the laboratory the next day, then she won't touch the key at all, so everyone can easily take the key and go to the laboratory to place a timing device, the laboratory is relatively remote, few people pass by, and the security guard only patrols once in the morning, and there is no camera, so the murderer can easily sneak in. Because she knows very well that Wang Xiaomeng is going to the laboratory today, she only needs to place a timed ignition device next to the fire point the day before, this device is based on the amount of oil to determine how long it can be stored, because Wang Xiaomeng will most likely spend time in the laboratory today, so the murderer only needs to put a small amount of engine oil and extend the timed time to do remote ignition. "Everyone was positive.

"Okay, let's analyze the second case, according to the footprints at the scene and the comparison of the suspect's shoe size, we found that there was no person who met the size 37, and the preliminary speculation was that the murderer's shoe size was less than 37, because the plus-size person wore small-size shoes, not to mention whether they could wear them in, even if they could wear them, it was very inconvenient to move, so I deduced that the murderer's shoe size was less than 37, and she should have spent a while to adapt to the ill-fitting shoes for this plan. Then there is the scene of the crime, the murderer after killing Rui Yi, specially hung her up, the murderer did a troublesome thing, I believe she must have her intentions, but we have not yet mastered, Rui Yi was deceived by the murderer's information to the toilet, the murderer is likely to be hiding in the toilet at the time, waiting for Rui Yi to come, we found that there is a corridor on the third floor of Building A that can cross to Building B, which can save two-thirds of the time, so the murderer does not need to walk from Building A to Building B, he can reach the second floor of Building B, These are the general analysis of the case, and now the clues are missing. Han Sicheng continued to affirm Mingyu's words and said: "Xiao Shen's analysis is very reasonable, and I also feel that the truth is getting closer step by step, but we still lack a lot of clues, I hope everyone will work together to find out more clues and evidence." Shen Mingyu already has a general understanding of the case, but he still has no eyebrows about the case of Lan Yingxue jumping off the building, he came to the window where Lan Yingxue jumped off the building before, and found that there was a water pipe that went straight to the sewer next to it, this water pipe has been full of ash because no one has wiped it all year round, but there is no dust in one place, he carefully checked the water pipe, and found that there is no dust in the place formed a circle, this trace, like a rope, since there are traces of the rope, there must be something left by the murderer that cannot be taken away, He went to ask his colleagues who had previously surveyed the scene if they had collected any evidence, and a young man who had investigated told him that he had found a severed black rope at the scene, and Shen Mingyu suddenly understood the murderer

"Lan Yingxue" jumping off the building. If you want to finish it in the fastest time

"Stealing beams for pillars", that can only be in that place. After thinking about it, Shen Mingyu ran to the end of the corridor on the 5th floor, and as he expected, he found that the dust was almost all over the walls and the edge of the bed, but there was no dust on the windowsill and window edge, which confirmed his conjecture even more, by the way, no wonder it felt strange at that time.

He ran back to the 6th floor and told his colleagues his conjectures: "Everyone, I seem to know the modus operandi of the second case, it was not Lan Yingxue who jumped off the building by herself, but the murderer who disguised himself as Lan Yingxue and jumped down." Han Sicheng interrupted: "Won't the murderer hang up if he jumps down?" Shen Mingyu went on to explain:

"So, my fellow investigators found a broken black rope at the scene, and I found that the large water pipe next to the windowsill was covered with dust, but there was one place that was unusually clean, shaped like a trace of a rope in a circle. Therefore, the murderer's modus operandi should be like this, she called Lan Yingxue in advance or brought her to the end of the corridor on the fifth floor under the window, and then stunned her, and took advantage of the fact that everyone was asleep in the middle of the night and the power was off, she took out the high heels that had been placed in the corridor in advance, changed into Lan Yingxue's same pajamas, and made a noise to attract everyone to come, her purpose was to attract everyone, so that everyone could witness the scene of Lan Yingxue jumping down, because the distance was very far away, and the light was very dim, only the faint light of the flashlight, She put on the same pajamas, so that everyone, including me, had a preconceived idea, let us mistakenly think that that person is Lan Yingxue, she should tie one end of the rope with a dead knot around the water pipe, and then tie the other end around her waist, because the rope is black, according to the situation at the time, we can't see it at all, and then she calculated the height, jumped to the windowsill on the 5th floor downstairs, quickly cut the rope short, and then threw Lan Yingxue down from the 5th floor, the only flaw in this technique is the time difference, Because the arrival of the sound of jumping down directly to the 2nd floor will be much faster than the arrival of the sound of this operation, but the murderer took advantage of the panic of everyone at the time, and covered up this fact very well, even I was bent on running to the window to check the situation, and I didn't pay attention to the problem of the speed of the sound coming, I just thought of it, I did not hear the sound immediately when I fell that day, and it stands to reason that the sound should be heard soon when I fell from the 6th floor to the 2nd floor platform, and the murderer took advantage of this. Now we are only partially clued and evidenced. ”

"Xiao Shen is amazing, Niu Xiao Shen, it turns out that it can be like this" Everyone's praise was endless, but Shen Mingyu was not complacent, because he hadn't found evidence yet, and he couldn't slack off yet.

In the evening, the three girls planned to go out to eat alone, although Han Sicheng said that it was dangerous, but the girls said that they didn't like the feeling of being stared at all the time, and promised not to go to a place with few people, Han Sicheng couldn't help it, so he could only let them go.

Shen Mingyu also took advantage of this to plan to have a meal, he hadn't eaten on time for a long time in the past few days, Shen Mingyu walked to the cafeteria, he suddenly saw Ning Lin's figure, didn't she go to eat, Shen Mingyu thought to himself, Shen Mingyu decided to follow her secretly.

Shen Mingyu followed all the way and found that Ning Lin had come to a gym next to the school, what was Ning Lin doing at the gym, Shen Mingyu decided to wait nearby to see the situation.

About 40 minutes later, Ning Lin came out of the gym, wearing a sports vest and a jacket in her hand, walking in the direction of the school.

Shen Mingyu saw something unbelievable to herself, Ning Lin's arms were unusually developed, and her muscles could be seen clearly, no wonder she usually wore long sleeves, and I heard them say that even in summer.

Shen Mingyu didn't continue to follow Ning Lin, he planned to go to the gym to ask about the situation, and when he came to the gym, he saw a fitness coach drinking water, so he asked: "Hello coach, do you know the girl who just came, I am his friend." ”

"Do you say Ning Lin, I'm his coach." The coach replied.

"I want to ask her how long she's been at the gym."

"It's been about a year." Shen Mingyu had a conversation with the coach, and finally, under the coach's narration, he knew Ning Lin's secret, the coach said: "Ning Lin was still very thin when she first came, and the whole person was listless, I happened to be here that day, so I asked her if she wanted to work out, she said that she had become stronger in fitness, would she not be bullied, I didn't know what she meant at the time, so I told her that fitness does make you stronger, but fitness is not a tool for violence, and she cried and said, why can people keep bullying her." , and even if I get stronger, I can't fight back against them, then I understand, she has experienced school bullying, she told me about her experience, she is often bullied and bullied by her roommates, but she is too cowardly, she can't do anything, I pity her, but I can't do anything about things in school, I patiently taught her how to exercise fitness, I thought at least she can defend herself, but she has come less recently, and she has less words, I asked her and she just said lightly that it's okay, I feel that she has changed, and the original Ning Lin is not alone. After listening to the words of the fitness coach, Shen Mingyu finally understood the truth of the whole thing, it turned out that it was just Ning Lin who was confusing everyone, and there was no threatening letter at all, the thing mentioned in the threatening letter was campus bullying, so Ning Lin used herself as a bait to take revenge on the people around her one by one.

Shen Mingyu hurriedly said goodbye to the fitness instructor and rushed back to school, now everything was clear, only the key evidence was missing, and he had to race against time.