"The Yushan Lake murder case, I observed the photo of Cai Yifan's body. There was a slight bruise on his ankle, which indicates that the killer submerged underwater, grabbed Cai Yifan's ankle to prevent him from surfacing, and eventually drowned him. However, this bruise is indeed very slight, almost invisible now, so it's not surprising that the forensic doctor didn't notice it."

"But wait, to grab Cai Yifan's ankle, the killer must have been beneath him. To drown him, the killer would need to keep his mouth and nose submerged the whole time. Following this logic, the killer must have been underwater the entire time too. Was the killer a mermaid who could breathe through gills? Otherwise, the killer would have drowned as well while drowning Cai Yifan."

I had my suspicions, but I didn't dare voice them. The leaders exchanged puzzled glances.

Zhang Weihua didn't mind everyone's reaction and continued, "The expert group from the provincial hospital has already arrived in Binhai, ready to study Shen Guochang's body. But I don't think it's necessary. Shen Guochang's cause of death is not malaria, not a central nervous system virus, nor sepsis."

"Then what is it?" someone curiously asked.

"Rabies!"

"I visited the Second Hospital, and a nurse on duty reported that Shen Guochang rarely drank water during his hospital stay. Considering his nervousness and hallucinations, I've basically concluded that Shen Guochang died of rabies. And Shen Guochang's home happens to have a dog. Director Wang, please send someone to capture that dog for examination, if it's still alive."

"But... a dog isn't a robot. Why did it only bite Shen Guochang?" I couldn't help but ask.

"That you can think of this question shows you're using your brain," Zhang Weihua said with an appreciative smile. "I examined Shen Guochang's body and detected a faint fragrance that differed from the shampoo and soap he had been using these past few days. According to my inquiries, Shen Guochang also didn't have the habit of using perfume. Therefore, I deduce that someone had applied a specific scent on Shen Guochang in recent days, a scent that could trigger aggression in a rural dog."

"No wonder that day Chen Jiafei was barked at by a dog and didn't run when he saw Shen Guochang approaching. It makes sense now. He tampered with the dog and deliberately provoked a conflict with Shen Guochang and others. During the physical contact, he also tampered with Shen Guochang," I suddenly understood.

Zhang Weihua turned to me, "What do you think of the suspect? Is it Chen Jiafei, or someone else?"

"Chen Jiafei definitely participated. He might be the sole perpetrator, or he might have had accomplices."

Zhang Weihua nodded and looked at Director Zhang, "Binhai City is full of talent. This comrade is experienced and quick-witted. I want to recruit him into the special investigation team."

Director Zhang's face brightened, "Xiao Cao was already responsible for the 927 case and is quite familiar with the situation. I support assigning him to the special investigation team."

I had just breathed a sigh of relief when the phone on the director's desk rang. He picked up the receiver, listened for a while, and then put it down with a serious expression.

Deputy Director Wang asked nervously, "Is it another threat call?"

Director Zhang nodded, "The reporting center informed us that the killer has declared he will kill the Xiao brothers, Xiao Delong and Xiao Dehu, within seven days, by October 17th."

He took a sip of water, "Principal Zhang, what do you think? We're all at our wits' end here. We rely on your expertise."

"Director Zhang, you're too kind. I'm just a teacher now; you all are the experts. If you're asking for my opinion, I suggest immediately transferring the Xiao brothers to a safe house and using all available police resources to protect them comprehensively."

"Should we detain Chen Jiafei?"

"We can monitor him but don't need to detain him. Chen Jiafei was just released, and he has an alibi for the recent case. We must protect public safety while also abiding by legal regulations."

Thinking about how we had previously detained Chen Jiafei without cause for seven days, I glanced at Team Leader Liu. He turned his head and showed me the back of it, silently signaling, "We don’t know anything."