Song Yuqiang said dejectedly. "Wasn't that night my brother's birthday? I’ve been studying away from home all this while. This year was my brother's 30th birthday. I bought his favorite chocolate cake to celebrate his birthday... I rang the doorbell that day, but nobody answered. But the lights inside were on. I went round outside and looked in through the window. I was so scared that I dropped the cake on the ground. He... He had collapsed onto the floor and his body was covered with blood... I knocked with all my might on the window and called him, but got no response… I was terrified, so I came back quickly."

Chen Shi asked, "Why didn't you call the police?"

"I... I was terrified. My mind was blank."

"You didn’t even inform your parents?"

"How can I tell them this kind of thing?! They were still talking about Yuwen's girlfriend the next morning. They talked about it with so much enthusiasm. I was so worried that I didn't even know what the breakfast I ate tasted like. I didn’t know how they’d react to such news."

"Song Yuqiang, do you want me to expose you? You'd better confess honestly now, or we can talk elsewhere. You saw the body but didn't call the police. Who would do this? The murderer!"

Song Yuqiang was frightened and broke out in a cold sweat. "How could I have killed him? You also checked that he was shot and killed. How can a college student like me find a gun?"

"Then why didn't you call the police?"

"How many times do I have to tell you that I was terrified?"

"I'm afraid there’s another reason. In fact, we’ve already found out, otherwise we wouldn’t be here."

"You... Found out..." Song Yuqiang looked terrified, clutching his pants tightly. "I didn’t plan to poison him. I just wanted to prank him. The cake was filled with laxatives. You can get it from any pharmacy."

What he said should be the truth. If there was really poison in the cake, the scavenger father and son would not have been so lucky.

"You were holding the cake with the ‘added ingredient’ in your hands and went to look for your brother late at night. It turned out that he was dead. You were afraid of being suspected by the police, so you didn't call the police. But the surveillance camera caught you and two unlucky scavengers ate the cake that you threw away. They’re now lying in hospital."

"Huh?!" Song Yuqiang was shocked. "How could it be so coincidental? Are they okay? I'm willing to pay the medical expenses."

"That's good, but why did you want to take revenge on your brother?"

"..."

"If I’m guessing correctly, you two fought a few days ago. I noticed the scabs on your knuckles."

Song Yuqiang covered up his fingers subconsciously. "Forget it, he’s already gone. I'll tell you, so that you stop suspecting me. It was my brother who was disloyal and snatched away my girlfriend!"

"Du Juan was formerly your girlfriend?"

"Yeah, things happened a year ago. I met her at the club and we got along quite well. Once, she said that she had a toothache. I said I would recommend a famous dentist to her, which happened to be my brother! At the time, I didn’t know they got together. I was stupid and kept texting her. I felt like she was getting colder and colder towards me. I was studying elsewhere at the time. I thought she might have gotten a new boyfriend. Although I tried to persuade her to stay, in the end, we still broke up. I was upset for one whole month...”

"Afterwards, when we were having our family dinner last week, my mother said that she would introduce my brother to a girl. He said that he already had a girlfriend. My mother asked who she was. He revealed some things about her. The more I listened, the more I felt like something was wrong. The time they met was exactly when Du Juan had a toothache. Of course, my brother noticed my reaction and then revealed to me that his current girlfriend is Du Juan. I got angry instantly and I beat him up, cursing him saying that he was worse than an animal, even snatching his younger brother’s girlfriend away.”

"The more I thought about it, the more angry I got. I scolded Du Juan online. My brother kept texting me to apologize. Right on his birthday, I pretended to accept his apology, bought a cake, and added a pack of laxatives inside. I just wanted to let him have diarrhea for a few days and teach him a lesson, who knew... Haii!"

Song Yuqiang recalled the past events with sincerity and Chen Shi felt that he was telling the truth. Furthermore, Song Yuqiang didn’t match the characteristics of the murderer. He asked, "Okay, we won’t delve into this matter further. Let me ask you something. Does your brother have any secrets?”

"Secrets?"

"Did he hurt any women in the past?"

Song Yuqiang was shocked for a moment. "No? I don’t think so. If there was anything, I’d definitely know. He tells me everything... Of course, my brother belongs to the type who refuses nobody, but I’ve never heard of him cheating on anyone or getting someone pregnant and so on. Do you suspect that this was a crime of passion? But the other party has a gun. The murderer must come from an unusual background. Could it have been done by the triads? But my brother is a dentist. How could he have offended them?”

"Okay, don't talk to yourself anymore. We’ll continue investigating the case! When is your brother's funeral planned to be held?"

"It will be held sometime soon."

"Leave me your contact details. I will come to offer my condolences."

"Okay, I didn’t know that the police are so kind. Thank you."

After exchanging contact information, Chen Shi asked for another sample of his fingerprints, and then asked, "What kind of person is your cousin Wanjun?"

"Her? She's our younger cousin. We used to play together when we were children. Later, she went to a boarding school and got admitted to a university in Australia. Now she’s studying abroad!"

"It sounds like her family background is pretty good."

"You’ve misunderstood. Her family is relatively poor. Her parents are laid-off workers and have borrowed a lot of money from my family! My words might be a bit much, but it’s true that my family is pretty well-off and there are quite a few relatives who come to ingratiate themselves with us. My parents are also quite generous and often lend money to our poor relatives.”

"It seems that your parents are pretty good people."

"Yeah, they’re overly accommodating. My dad is the eldest, so he often helps his brothers and sisters out!"

"Do you have a picture of Shi Wanjun?"

"Why are you so interested in this..." Song Yuqiang smiled and took out his mobile phone to show Chen Shi Shi Wanjun's circle of friends on WeChat and her Weibo. There were many photos that she had taken abroad, and most of the Weibo posts were written in English.

Chen Shi wrote down the girl's WeChat and Weibo account IDs. He bid goodbye to Song Yuqiang. When they left the housing district, he said, "This kid was lucky. When he rang the doorbell, the murderer was probably still in the house. He almost got murdered too."

"You seem to be very interested in the girl studying abroad. Shouldn’t she be the least likely to have committed the crime?"

"A recurring name. I will always pay attention to that."

"Right, Song Yuqiang has been ruled out. That is to say, everyone who entered and left the housing district that night was not the murderer. The murderer was not recorded on the surveillance video at all!"

"She wasn’t captured on the footage, but she deleted it. How did she enter the duty room without being captured?" Chen Shi furrowed his brows in thought. He didn't believe that the murderer was an invisible ghost. There must be some kind of explanation.

"Let’s head back!" He said.