Chen Shi called Peng Sijue and wanted him to send a few forensic police officers over to identify the traces, but he couldn’t get through. Lin Dongxue said, "Captain Peng is still dissecting Little Wei's body now, right? Why don't we come back tomorrow?"

"Someone climbed out of this window that night. The main point is not the traces on the window frame, but the suspicious fiber on the pipe. Can we take it off ourselves?"

"That isn’t a good idea. I just saw it. That piece of fiber is on the fifth floor. It's too dangerous to climb out of the bathroom window in order to pick it up.

"Then we should go to the fifth floor!"

Lin Dongxue smiled bitterly. "All right!"

The two knocked on the door of the tenant on the fifth floor, took the small piece of fiber stuck in the pipe from the window and put it in an evidence bag. Chen Shi said excitedly, "As long as we find out who left it, we’ll know who killed Duan Lin!"

"Why wouldn't it be left by the corpse dismemberer?"

"Uncle said that the door of the house was open when he came back on the morning of the 24th. I checked before and the lock had no traces of being picked. It had been opened with a key. The person with the spare key is most likely Duan Lin's boyfriend. After Duan Lin committed suicide, her boyfriend came here to deal with the aftermath and took her cell phone away. At this time, the dismemberer arrived, and the boyfriend escaped through the bathroom window in a panic. Then the dismemberer divided Duan Lin's body in the bathroom, cleaned up the scene before dawn and also took the corpse parts away."

"So did the dismemberer see her boyfriend?"

"He obviously didn’t see him."

"Then how did he know that her boyfriend was one of the nine? How did he know Duan Lin committed suicide?"

"Yes, how did he know?" Chen Shi's eyes lit up. "I understand now. He’s also one of the nine!"

Lin Dongxue's eyes widened in surprise. "This seems to make sense... but this speculation only holds water based on the premise that the uncle didn’t lie this time."

"Just check the surveillance footage in the bus waiting room to see if he lied..."

"Shall we go to the bus station now?"

Chen Shi checked his watch. It was already pretty late. "No, let’s go and meet Zhang Xiao!"

When they called Zhang Xiao, he said that he was off work and was waiting for a bus on a certain street. Chen Shi told him not to wander off, and that they would arrive immediately.

Half an hour later, the two met Zhang Xiao. He was dressed more decently since he had just gotten off work, and he smelled of shoe polish. As soon as he saw Lin Dongxue, he greeted her with a smile on his face. Chen Shi said, "Let's find a place to talk."

"There’s a Starbucks nearby."

When they got to Starbucks, Zhang Xiao expertly ordered a lot of food and drinks, as if he was a regular customer. Chen Shi wondered if this kid was going to scam him out of a meal. Zhang Xiao finished ordering and asked, "Aren't you two going to order?"

"No, since you’re the only one eating, you pay for your own food."

"Oh, why are the police so stingy?"

"It's not easy to make money... Let's talk about business. What were you doing on the night of the 23rd?"

"Having dinner with friends."

"Nine of you together?"

"No, it was just me, XX, XX, XX, XX, and XX. The six of us."

"Why was it the six of you?"

"Because we were friends to begin with. Ah, I forgot to mention that XX and XX and I were from the first intake, the other three were from the second intake, and Little Four, Little Wei, and Big Ox were from the third intake."

"Why make such a distinction?"

"Because the nature of our group is equivalent to a training course. Little Four and the others hadn't graduated at the time and were taking online classes."

"Who holds the online classes? Do you have a teacher?"

"They’re usually video lectures. Sometimes, I’ll be a guest lecturer and personally guide new students." Zhang Xiao displayed a proud expression.

Lin Dongxue took out a small notebook and wrote down this clue. Zhang Xiao mentioned the names of several teachers.

At this time, the waiter brought the food that Zhang Xiao had ordered. Zhang Xiao was deliberately attentive and said, "Let's eat together. Since you guys asked me to come here for questioning, isn't it normal for you guys to treat me to a cup of coffee?"

Chen Shi glanced at the coffee, tiramisu, sandwiches, and pudding piled on the table, and smiled, "If you ordered a cup, I can treat you, but I can't afford so much."

"In that case, can you settle the bill for this cup of coffee?" Zhang Xiao said with a grin.

Chen Shi thought that this kid was really shrewd. "As long as you answer the questions honestly, a cup of coffee is fine."

"Go ahead and ask."

"Where did you go after the dinner gathering?"

"I went home!"

"Where was the dinner held?"

"Caiyuanzi Restaurant."

"Till what time?"

"It was past 10:00PM."

"You took a taxi back alone?"

"Yes."

Chen Shi stretched out his hand. "Let me see your taxi records from that day!"

Zhang Xiao stopped eating, raised his head from the cake, and a trace of panic passed across his crumb-stained face. He said, "It’s been deleted!"

"It doesn't matter. Show me your phone."

"It’s really been deleted."

"Actually, I’m not a police officer. I’m a criminal investigation consultant. My main job is working as an Internet ride-hailing driver. I know this system extremely well. Show me your app. It doesn't matter if you deleted it. I can find your records."

Zhang Xiao didn't speak. His brows were tightly-knitted and he didn’t notice that his right hand was crushing the cake into crumbs.

This detail didn’t escape the eyes of Chen Shi and Lin Dongxue, and Lin Dongxue thought to herself that the case was solved now.

"You’re Duan Lin's boyfriend, the one who made her commit suicide, right?" Chen Shi enunciated every word.

"No, no, no!" Zhang Xiao desperately denied. "I don't know her. I have a girlfriend. If you don't believe me, I will call her now."

"This proves nothing. It's normal for a person like you to have several girlfriends at the same time."

"What do you mean... What do you mean?!" Zhang Xiao slammed the table and stood up. "If you look down on PUAs, then just say so. With my looks and family background, would there be any woman out there who wants me if I am earnest? Two years ago, I hadn’t even held hands with a woman. If it wasn't for PUA, I would still be single! To put it bluntly, you’re just envious that I can attract the opposite sex. All crows under the sun are black. We’re all animals that think with our lower bodies. No one needs to look down on anyone else. You dare to guarantee that you have never cheated on Officer Lin behind her back?"

Zhang Xiao suddenly started to purposely make trouble. He rambled incoherently, causing many customers in the cafe to look over at them. Chen Shi looked on coldly. The source of his anger was a guilty conscience.

"Can we talk like adults..."

Suddenly, Zhang Xiao fell to the ground, convulsed all over, and foamed at the mouth. Chen Shi thought he was acting at first, but it didn’t seem so, so he instructed, "Hurry up and call an ambulance!"

Half an hour later, Zhang Xiao was taken to the hospital, and Lin Dongxue asked, "This illness happened too coincidentally, right?"

"It's a coincidence, but we already know that Zhang Xiao is Duan Lin's boyfriend."

"In that case, is he in danger?"

"Danger?" Chen Shi thought of something, "Yes, the murderer was in the group. When he lied previously, the murderer had already seen through him! The murderer might come and look for him tonight!"