Chen Shi and Lin Dongxue searched the area around the neighborhood, but they couldn’t see any signs of people having climbed over the wall. They also made copies of all the surveillance videos they could find in the surrounding shops.

The two of them drove back to the station after the police had already left. By that time, the preliminary autopsy report had already come out. The victim had a double-edged weapon pierce his aorta and had died of pulmonary embolism. Alcohol was detected in his bloodstream. His blood sugar level showed that he seemingly just had a meal.

In addition, gamma-hydroxybutyric acid, commonly known as "g water", "amnesia water", and "obedient water", was found in the car. It is a psychotropic drug and is often used for date-rape purposes.[1]

A cup of milk tea had been spilled in the car and it contained the same drug components. There was unidentified saliva on the milk tea’s straw. It was suspected that the killer had drunk it. Judging from the concentration and the amount of liquid remaining in the cup, the killer had taken in at least 5 mg of this drug.

Lin Qiupu said, "It seems that the murderer met the victim, but the victim had indecent intentions and put the drug into the drink. That’s why she committed this crime hastily and didn’t put a hawthorn berry in the victim’s mouth.”

Another police officer said, "The victim has a prior record of rape. He must do this sort of thing frequently to have this drug ready in the car.”

"It seems that the killer unintentionally left us many clues. From the guide cane, it does point to her being a blind person... Check for manufacturers and retailers." Lin Qiupu asked Chen Shi who was silent. "What do you make of this?"

"Can ‘amnesia water’ be used as an aphrodisiac?" He asked.

"No, it will only put people in a daze. But from the amount that she ingested, she should still be able to leave the scene of the crime." Peng Sijue answered.

"I was just thinking. If the killer can derive huge benefits from the murders, how did she find out about it? She must have killed someone before, purely by accident or just out of defense. Tomorrow, Dongxue and I will look for old cases and see if there are people that fulfil these conditions."

"I don't agree with you regarding the great benefits that the murders bring, but regarding the killer being blind, I agree that it’s a truth that has been pretty much nailed down." Lin Qiupu said, "I visited the friends of the first three victims. Song Jicheng's buddy said that he was told by Song Jicheng himself that he had gotten acquainted with a blind woman and planned to meet up with her in person. The meeting time was basically the same time as his murder."

"I think she must be quite the looker." Chen Shi said.

"Don’t you have anything constructive to say?"

"One more thing. You don’t need to check with the ophthalmology department anymore. From the killer’s actions, she is a 'veteran' blind person. Such blind people generally won’t continue going to the doctors. You can find blind people using blind people. The blind people in the city should know each other.”

"But there are a lot of them. I didn't know before, but Long’an has so many blind people."

Chen Shi shrugged. "I'm going home."

The investigation of the case was progressing in full swing. During the past few days, each person in the task force met with a dozen blind people over the past few days. Chen Shi and Lin Dongxue also visited some blind people who had prior criminal records, but none of them met the requirements.

The person he was trying to find never appeared. The voice in his heart never said "It’s her" to him.

On the afternoon of June 15th, Chen Shi and Lin Dongxue went to see another blind person. She had been raped and had injured the rapist in self-defense. However, when they saw her, they found out that she was a 170cm girl on the slightly heavier side. She didn’t really match the killer’s characteristics that they had deduced.

Since they were there, Lin Dongxue still showed her badge to the girl and said, "Are you Kang Li?"

"Yes, you guys are the police? What happened? Was the rapist from two years ago caught?"

"We’re investigating a case and would like to ask you where you were on the evening of June 13th?"

"I was in the shop that day and the manager can testify to that."

"The blind people massage parlor in the alley below?"

"Yes, yes. What case are you investigating? Was the rapist from back then killed?"

Chen Shi interjected, "Why are you asking that?"

"You probably don't know, but that guy purposefully picked blind people. He was rotten to the core. When I injured him out of self-defense back then, I bit his ear. The police found him through DNA tests. I think he was called... Luo Shiyu. That's right. That was his name.”

"Has he committed another crime since then? How do you know that he only goes after blind people?"

"Because a few of my friends have also been through it. This guy has been on the run from the police. But lately, it’s like he’s disappeared. So, since you guys are looking for me, it would most likely be for this matter… Is he dead?”

"That is inconvenient for us to disclose right now."

"Tell me when it’s convenient to disclose it. Because of that incident, I’m now living in a constant state of fear."

"No problem... Do you know who he raped?"

Chen Shi wrote down a few names and said goodbye to Kang Li. He told Lin Dongxue to call the local police station and ask about the whereabouts of the rapist. Lin Dongxue exchanged a few words with the other party before covering up her phone with her hand in order to talk to Chen Shi. "They said that this person has disappeared for a year."

"Where does he live?"

"Guyi Lane on Caoshi Street."

"Let’s go and have a look."

"Huh? Are you suspecting that the rapist was killed by the murderer?"

"Since we’re just bouncing around trying to get leads right now, we might as well take a look."

After getting into the car, Lin Dongxue asked, "You said before that the killer derives huge benefits from the murders. What could it be?"

"For a blind person, what would be worth taking the risk?"

"It wouldn’t be to restore their vision, right?"

"That's what I was thinking."

"Are you teasing me? Killing people will allow her to see? How is that possible?"

"I saw the surveillance footage that day and I got this idea. I thought it was ridiculous too, so I asked Miss Gu... We spoke to each other via phone."

"What did she say?"

"She said that it’s possible. Psychogenic blindness, also known as dissociative sensory disorder, is caused by huge mental trauma, causing part of the person’s physical functions to be impacted or lost. But this loss is not the same as true blindness. Her eyes can still receive the visual signals, but she can’t perceive them. It’s like having a functioning monitor and a functioning computer but there’s something wrong with the wire connecting them.”

"I don’t understand!"

"In a nutshell, her eyes are fine, but she doesn't know that she can actually see. She thinks that she’s blind. Miss Gu feels that under the strong stimulation of murder, she is likely able to restore her eyesight for a short period of time. As a blind person, she was able to see the colorful world all of a sudden. This 'reward' is better than anything else, that’s why she’ll continue to kill again and again."

"Can there be such a motive for murder?" Lin Dongxue froze. "Are you sure?"

"It's just a hypothesis. After all, the probability of this kind of thing is extremely low, and it belongs to the category of medical miracles... We’ll start with high-probability incidents. Based on the times in which the murders were committed and her ability to meet with them alone, she seems to have a lot of free time. There’s a high probability of her living alone. In the past two days, we’ve checked a lot of schools for the blind, blind massage parlors, car-repair shops operated by blind people and other places. All the people we found were blind people who lived together with one another. If she lived alone and was a young and beautiful blind girl, it’s likely that she would be picked by rapists who actively chose blind people as their targets. They’d just try their luck with her.”

Lin Dongxue smiled. "After enough trial and error, the truth will pop out."

1. GHB has been used in a medical setting as a general anesthetic and as a treatment for cataplexy, narcolepsy, and alcoholism. It is also used illegally as an intoxicant, as an athletic performance enhancer, as a date rape drug, and as a recreational drug.