Lin Dongxue whispered to Chen Shi, "Xiaodong's statement matches with this. He said that she went upstairs at 10:00.”

Chen Shi nodded and asked Aunty Wu, "Why didn't you tell the police?"

"Wouldn’t you treat me like a suspect if I did? I didn’t expect this to happen when she came and took her ID. I was worried that as soon as I told you, I’d be treated like I was suspicious."

"Mr. Li wasn't there at the time?"

"Mr. Li went out to find her. Ranran came back in secret and had something to drink… The bottle that’s half finished in the fridge was hers. Then, she took her ID away. She said she wanted to run away from home in order to scare Mr. Li a bit by just staying at an Internet café or hotel overnight. I specifically asked her to be careful but she told me that everything was okay because all the places she planned to go to had surveillance cameras… Who would have known that something like that would have happened at 1:00AM!”

"You didn't tell Mr. Li? It seems you usually take her side." Chen Shi said.

"Haii, you don’t know how strict Mr. Li ’s parenting is. During the entirety of high school, there wasn’t a single night where Ranran could sleep more than six hours. Not only did she have to study all night, he also had home tutors touch up on things with her. If she even got a slightly lower score than what was expected of her, he got her to write a review analyzing the reason. She often wrote it while crying… I just think about how pitiful this child is. No matter how much better off she is in terms of family background, she suffered ten times harder than ordinary children, so I usually take special care of her. Oh, yes, when she came home last night, I gave her a bag of baked cookies."

"Her grades are pretty good. Why did Mr. Li trust the scammers and try to buy the test paper in advance?”

"Huh? How do you know about this? Mr. Li really wanted her to go to Peking University. Actually, I just want to say that all the prestigious universities below Peking University would accept her, but Mr. Li had one-sidedly set his sights on Peking University. They quarreled precisely for this reason and he even slapped her for it."

"Anything else you want to tell us?"

Aunty Wu shook her head.

Chen Shi took out the photo of the box-cutter and said, "We found Ranran’s blood on this and there was another person's fingerprints on it as well. You’re the one who cleans the room. The fingerprints are most likely yours, right? ... You realize that this evidence is detrimental for you, right?"

Aunty Wu was so scared she put her hand over her mouth. "I can explain this!"

"Then explain!"

"That was the time when Mr. Li forced Ranran to write a guarantee and told her to stop acquainting herself with a boy named Gao Xiang. She cried the whole night after writing that guarantee letter. The next day, Mr. Li went on a business trip. Ranran didn’t wake up even though it was 9:00 in the morning and she didn’t answer no matter how much I called her. It was odd to me because this child usually didn't sleep in. So, I took the key that I had and opened the door to check on her. I saw Ranran holding the cutter in her hand while laying down on the bed. Her wrists were all cut open. I was terrified and immediately dialed 120. Fortunately, her life wasn’t threatened. If Mr. Li knew about this, who knows how he would react? That’s why I kept this event a secret.”

"Do you know what the reason is? Is it because Mr. Li broke them apart?"

"No, no, she told me about it later. Actually, she only had good feelings towards Gao Xiang, but they weren’t dating. Gao Xiang sent her home that night, but he actually tried to take advantage of her while they were in a small alley. If there hadn’t been a kind stranger passing by, she would have been ruined by him. The more she thought about it, the more afraid she was. She didn't dare to go to class again and didn't dare to tell her family. That’s why she did such a silly thing!"

"So you hid the cutter?"

"I did. I was afraid she would do something like that again. I hid it behind the papers she had already done."

Chen Shi took the drink that Li Mengran drank last night as well as the cookies baked by Aunty Wu. She baked these because Ranran said that she loved to eat them. The cookies were tied up in small plastic bags and there were five bags in total.

Chen Shi said, "We’re not doubting you, but we have to ask you to go to the bureau and repeat these words just now to make a detailed statement. Because another person is suspected right now, your statement can clear his suspicion."

"If you don't doubt them, do you doubt me?" Aunty Wu asked worriedly.

"Why would that be? Firstly, you don’t have the motive. Secondly, you had no time. I know that you’re very good towards Ranran. Your testimony narrowed the time in which the murder occured, which is very helpful to our investigation."

"Okay, okay, you have to explain to Mr. Li."

"Of course!"

Lin Dongxue called the bureau and the case was now officially filed. However, the third team was responsible for it. After negotiating with Lin Qiupu, the third team agreed to participate in the investigation with Chen Shi and Lin Dongxue.

Lin Dongxue contacted the team leader of the third team and asked him to come and take Aunty Wu back to make a statement.

The two left and Chen Shi pressed the button for the elevator to go upwards. Lin Dongxue said, "You pressed the wrong button!"

"I’m going upstairs."

"Upstairs?"

"If what Aunty Wu said is true, I think Li Mengran still likes Gao Xiang. That’s why when Gao Xiang tried to do something indecent to her, she had a strong sense of heartbreak and decided on the extreme act of suicide."

"Do you think Gao Xiang is a suspect?"

"I can’t say if I haven’t seen them before, but I don’t plan to go to the school. The murder technique is so sophisticated. The murderer probably isn’t a student. Furthermore, the interpersonal relationships at school are very complicated. The two of us wouldn’t be able to get through everything. It’s better for the third team to wade through that muddy water instead!”

"You’re just going to sit here and steal the fruits of victory?"

"How can you say that? There are both slow and fast investigations. If there’s sufficient manpower, I would investigate slowly. Since we only have two people right now, I have to make haste! I’m making an internal list to see which people have the highest probability of being the murderer. We’ll investigate those people first. This method is a bit of a gamble, but it’s a solution for now.”

"But you always win your gambles!"

"It’s just luck!" Chen Shi smiled. In fact, what he really wanted to say was that it was because of gut-feelings and through simulating the murderer's thinking.

The two took the elevator to the top floor and went up to the rooftop, but the rooftop door was locked. Chen Shi told Lin Dongxue, "Go and find the property manager."

"Oh!"

As soon as Lin Dongxue went down, Chen Shi pulled out the lockpick from his pocket, quickly opened the lock, and called out, "Come back! Come back! Someone clumsy must not have locked it properly. It opened as soon as I pulled on it."

Lin Dongxue came up and looked at him inconceivably. "You're way too lucky!"

When they got to the rooftop, although it was late, the surrounding area was still visible since it took awhile for the skies to get dark during summer.

Chen Shi looked around and kept taking photos with his mobile phone. Lin Dongxue asked, "What are you taking photos of?"

"I’m trying to see where the murder took place. There was dirt on the head. Take a look." Chen Shi showed her the photos and the two discussed them one by one.

"Although the flower beds on the road have soil, it’s not possible since lots of cars come and go! Pass!"

"There’s a playground in this school and it’s very quiet at night, but would Li Mengran go there? Pass!"

After screening out a bunch of photos, there was still a place nearby that was left. It was a construction site. The two of them decided to pay that place a visit immediately.