I

On the afternoon of July 18, I was summoned to the head investigation quarters of Hangzhou Siji’qing police department.

The two people in the room stood up and nodded as I entered the room. One of them was a woman, wearing a police suit, and the other was a man in casual clothes.

“Officer Chiu, head of the investigation department.”

“Yuan Cheung, assistant of the Huili-Lai Case.”

Two mugs of freshly-brewed coffee rested on the table. Yuan handed me the case report binder, and I went through the present evidence. I closed my eyes to allow the clues to piece themselves together in my head, and gestured for Yuan to begin.

“Would you mind telling us, Mr. Shyu, one more time what had happened?”

“Of course not. Thank you, officer, and I would do whatever I could to assist you and Miss Cheung.”

I pulled out the investigation folder as he began.

“My wife, Mrs. Lai, disappeared in the middle of the night fourteen days ago. We went to bed at 10:30 as usual on July 4. At 5:30 the next morning, I woke up to find the space beside me on my bed to be empty. She never had the habit to wake up early in the morning, but I found her phone, purse and other belongings right where they were in the apartment, so I thought she just went out for a small errand. But, to my surprise, she did not come home for breakfast, and nor did she return that evening. The next day, that is, July 6, she was still missing. I found the situation odd, but I did not report to the police until at around 7:00 p.m. on July 6, after receiving a phone call from her boss that she did not go to work that day—you know, July 6 was a Monday.”

I felt my brain malfunctioning from the huge pile of oddities, and decided to start off by questioning in time order. “Were you and your wife alone in the apartment on the night she left home?”

“No. Our daughter lives with us, but she sleeps in the other room.”

“How old is your daughter?”

“13.”

“And how old was your wife?”

“52.”

I scratched my nose in thought. “So she had your daughter at 39.”

“I am her second husband.” Mr. Shyu added, having noticed the tone of doubt in my voice. “She had a daughter with her former husband, who is already 27.”

“And where does the elder daughter live?”

“Several blocks away,” He said as Yuan handed me a map, “which is why I delayed reporting the case—I thought she went to her house for the night.”

I frowned and jotted down questions on my notepad. I decided not to ask.

“Did we check the surveillance camera footage?” I turned Yuan and handed back the map.

“Yes.” Yuan flipped the investigation folder on her lap and pointed to the section on security cameras. “The camera in the elevator indicates that Mrs. Lai returned home with the younger daughter at 5:04 p.m. on July 4. After that, we checked the elevator camera as well as all 7 cameras on the streets in the neighborhood, and we did not see Mrs. Lai or anyone who looked similar to her, appear in the footage after 10:30 p.m. on July 4 until 5:30 a.m. the next day.”

“Was it possible to leave the neighborhood without being caught on camera?”

“No.”

“Absolutely not?”

“We have not found a route yet. But it is possible for her to move around the building without being caught on camera. The emergency stairs and the hallways did not have surveillance.”

“Then did you check the neighbors’ homes?”

“Yes, a thorough search of every room in that building. Not a trace of Mrs. Lai.”

“Did they use Luminol?”

I regretted that question as soon as the words left my lips. It was but an indication that I suspect Mrs. Lai have already died that day, and, what’s worse, it revealed my suspicion of Mr. Shyu. Luckily, from the composed expression on Mr. Shyu’s face, it appeared that he did not understand that Luminol was commonly used by crime scene investigators to detect human blood.

Yuan bit her lower lip. “Yes, but no result.”

I felt grateful to Yuan that she did not reveal to Mr. Shyu the function of Luminol in her reply, and keeping this mistake to ourselves. “The whole building?”

“Yes. Including the staircase, hallway, and ventilator. We did not find her fingerprints anywhere either.”

I placed a question mark on my notes and turned to face Mr. Shyu again.

“What did you and your wife do after she returned to the apartment that day…at 5:00 p.m.?”

“We had dinner, which my wife bought from the bakery. Then my wife helped our daughter with her homework as I vacuumed the house. We went to bed at 10:30.”

“And when did your daughter go to bed?”

“I don’t really know. Around midnight, I suppose.”

“Midnight? But she is only 13.”

“She had pretty heavy workloads almost every day. Besides, it’s pretty normal for a student to go to bed at midnight.”

Yuan nodded in agreement since she was a mother of a 12-year-old.

I stared in blank astonishment, for around ten years ago when my son was around 12, he never had nearly as much work as these children nowadays. “Was the dinner pleasant?” I forced myself back to the topic.

“Quite.”

“And how was the homework session with your daughter?”

“Same.”

“Really? I used to argue with my son every single time when we discuss schoolwork.”

“Maybe daughters are different from sons,” Mr. Shyu smiled drily, “but we almost never argued with each other.”

“So you had a stable relationship with your daughter and wife?”

“Yes, I would say that.”

I scratched my nose in thought. “What about the elder daughter?”

“What do you mean?”

I noticed a tone of nervousness in his voice, but his facial expressions appeared to be calm. “How was your relationship with your wife’s former husband’s child? Were you two in any kind of conflict because of the second marriage?”

“Oh no, absolutely not.”

“Then, do you contact her often?” I was waiting for this sort of breakthrough, like a lion drooling over his prey.

“Not really.”

The tone of nervousness had faded away, and I knew he had already composed himself. At this point, it would be nearly impossible to seek further evidence.

“Thank you.” I jotted down a final line on my notepad and paced back to the other room.

II

“Officer Chiu.”

I looked up and saw Yuan peeking into the room, and nodded for her to enter.

“Sir, new evidence.” She handed me the investigation binder and flipped to the final page. “We found in the communal garbage disposal a delivery receipt to Mr. Shyu’s home. It was medicine for insomnia, delivered to Mrs. Lai but received by Mr. Shyu in the afternoon of July 6.”

I was almost paralyzed with utter shock. “Mrs. Lai took sleeping pills?”

“Yes. And we did find the diagnosis in the apartment, which states that it was because of anxiety.”

“Anxiety for what?”

“Not certain. We’ve contacted her doctor, who said he had no idea since she came to him only last month.”

“Were there remnants of sleeping pills in the apartment?”

“No. Mr. Shyu said that was the reason why Mrs. Lai ordered a new delivery.”

“But we don’t know that for sure.”

Yuan bit her lower lip, and I knew exactly what she would say. “Sir, you seem to be strongly suspecting Mr. Shyu.”

“Frankly, yes.” I flipped open my notepad. “Back to the evidence.”

Yuan sat down at the table as I spoke.

“Three queer things I jotted down during our conversation. Firstly, Mr. Shyu reported the case 38 hours after he noticed Mrs. Lai was missing, and he said he suspected she stayed at her elder daughter’s home. But he did not call the elder daughter to confirm.”

“Indeed.” Yuan interrupted. “We have checked Mr. Shyu’s phone.”

“Thank you. And this might indicate, even though he himself denied it, that Mr. Shyu had a conflict with the elder daughter. Would it be possible that the problem with the elder daughter was related to the second marriage, which means that the peaceful relationship between Mr. Shyu and Mrs. Lai is also false?”

I paused for Yuan to type up the idea on the case report and continued when she looked up.

“Secondly, about Luminol testing and how Mrs. Lai was killed—and yes, I do believe Mrs. Lai was already killed on July 4. Using sleeping pills would be the perfect solution since it did not involve blood. The only part missing here is proof that there were enough sleeping pills in the apartment on the night of July 4 to kill Mrs. Lai. If only we could find the receipt or wrapping of her last order, to be certain of how many pills were given to her, and how much she should have taken daily.”

“I will tell the investigation team on scene.” Yuan quickly jotted down a to-do note to herself.

“Thank you. Notice there could be two directions in this assumption: if it involves premeditation, then the delivery on July 6 might be a disguise. Proof for that might lie in the shopping record and the IP address of the user. But if it does not involve premeditation, then did the murderer know when the order would arrive, and used this knowledge to his or her advantage?”

Yuan understood my implication and typed on her computer.

“And the final point—what was Mrs. Lai’s occupation again?”

“She was…a janitor at an investment company.” Yuan flipped through the binder to confirm.

“And could a 52-year-old janitor tutor a 13-year-old student’s schoolwork?”

Yuan tilted her head in thought. “Not likely. Fifty years ago—1970—they did not have compulsory general education back then.”

“I thought so. And that makes Mrs. Lai’s timeline on the night of July 4 rather odd.”

Yuan nodded in agreement.

“Our following investigation would be divided in three directions: Mr. Shyu, the elder daughter, and the younger daughter. I would head to the elder daughter’s apartment at once and talk with the younger daughter tomorrow. Would you please take charge of the investigation against Mr. Shyu? Especially in relation to the sleeping pills.”

“Absolutely.”

III

The elder daughter, young Miss Luo, lived alone in a single-suit apartment in the center of the city. She greeted me with a gratuitous smile, and I understood that she already resigned from her job in order to aid investigations.

We sat down on two sofas shaped like swings. The living room was decorated with vines and colorful small lights. Miss Luo’s apartment was nothing like Mr. Shyu and Mrs. Lai’s. Their house, according to photos from the investigation binder, was kind of messy, with every drawer stuffed full of daily appliances and items piling up even on the floor. Miss Luo’s apartment, on the other hand, did not have many things. She must have spent a lot of time decorating her home into a paradise for a young single woman.

“Did your mother visit you often after you moved here?”

“Sort of. She came once a month, to chat and to bring me things from home.”

“Had she ever slept over at your place?”

“Rarely. You see, it is not that convenient, since this is a single suit and there’s only one bed here. So more often I sleepover at my mother’s house, during vacations and festivals, because my little sister and I could share a bed.”

“So you have a friendly relationship with your younger sister?”

“Yes, I love Lini.”

“Then have you ever minded that your parents broke up?”

“Well yes, of course, but only when I was really young, and back then I did not know my birth father did such a terrible thing to betray my mother.”

“And do you support your mother’s second marriage?”

Miss Luo smiled. “I know it’s unbelievable, but yes. She married stepfather when I was 14, and had Lini right after that. I was already a high school boarding student, so I was often away from home. I thought it was nice for my mother to find someone to accompany her after I left.”

“It seems that you cared about your mother, even at a young age.”

“Of course. I was so lucky to have a parent like my mother. She was gentle and supportive of me whenever I felt even the slightest bit of doubt. Without her encouragement, I would not have majored in French and Literature in university, and I would never have become a translator, which I now know is exactly what I dream of doing for all of my life.”

“I see your mother’s influence on you,” I said with a smile. “But have you ever felt that your stepfather interrupted your relationship with your mother?”

“No, never. I do not love him as much as I love my mother and sister, but I do not mind him becoming a part of our family.”

“Understood.” I scratched my chin in thought. “So do you contact your stepfather often?”

“Not really. We have nothing to discuss. Every time I voluntarily call him was to discuss matters around Lini.”

“What sorts? Just out of curiosity, of course.”

“No, sir, I do not mind. Anything could aid investigations right now, and I would be willing to help. It’s just that a year ago when Lini first entered middle school, I felt Lini was under too much pressure. She studied until midnight, took all sorts of tutor classes during weekends, and never got to play with her classmates or merely do things she is interested in. I thought my stepfather was at fault since my mother never pressured me this way when I was young and I could not even picture my mother doing such a thing, even though Lini told me that our mother was giving her too much pressure. It is impossible, our mother, such a gentle figure in my memory, so I thought it was a joke. Later I realized all kids nowadays suffer this type of pressure, and my stepfather and mother didn’t really have a choice.”

“I understand exactly how you feel.” I shrugged. “My son is only slightly younger than you, and when he was young I never gave him any stress either.”

“And it’s not as if children’s interests are worthless or evil. Lini does not play video games. She likes reading, which is an unbelievably beneficial activity, and her understanding of psychology could rival that of a college sophomore. But she never had any free time to read after she entered middle school.”

“Psychology? A 13-year-old girl?”

“Yes, I also thought it was unbelievable. Lini is an incredible child, the smartest and kindest person I know. I know she would turn out to be phenomenal if only people could stop restricting her.”

“Have Mr. Shyu and Mrs. Lai ever argued about giving pressure to Lini?”

“Not really. They are very much in love, and it is almost a social consensus that such pressure is necessary—it’s not even open to debate, which is frightening to me.”

At that, all of my questions are finished. I left her apartment at 9 in the evening.

The next morning, I received two pieces of information at the police station. They found a passage to leave the neighborhood without being caught on camera that leads right towards the Jinghang Canal, which dumps directly into the sea less than 20 kilometers downstream. A search team was already at the estuary in search of the body. Additionally, Yuan reported that she found an electric receipt of Mrs. Lai’s last purchase of sleeping pills, and had proof that she should have had enough pills on the night of July 4 to kill an adult. The new purchase was made from the computer in Mrs. Lai’s home, but all three family members shared the same computer and account.

Mr. Shyu was already under arrest, while Lini was under the supervision of Miss Luo.

IV

I met young Miss Lini in the vine-covered living room that morning after she finished her online lesson that morning.

She was exactly as Miss Luo described, constantly quiet and by herself. But I could tell from her furtive glances at me that, luckily, she still possessed the curiosity of a 13-year-old.

“Your sister told me yesterday that you are interested in psychology? You know, as a police officer and especially a detective, we were required to take psychology courses in college.”

Her eyes lit up at my words, and she straightened up her back on the swing sofa. “Did you get to do psychological experiments?”

“Sometimes.”

“Then…have you ever done rat-depression experiment?”

I saw her eyes sparkle with a genial desire to know, and that spark assured me that her quietness was all imposed upon her and that her true self was full of curiosity, just like any teenager of all times.

“I forgot which psychologist, but it was a recent experiment, first conducted in 2012.”

“Then I might not know that one. I graduated from college nearly thirty years ago.” I chuckled.

“It was my favorite experiment, the one experiment that got me interested in psychology. These psychologists put three rats into three separate boxes, with a button in each box. In the first box, whenever the rat touched the button, the scientists gave it food. So the rat kept pressing the button. In the second box, whenever the rat touched the button, the scientists gave it a mild electric shock. So the rat stayed far away from the button. In the third box, when the rat touched the button, the scientists would give it either food or an electric shock at random. In the end, the rat was so confused that it died of depression.”

“So unpredictability was what caused depression?”

“Exactly.”

She fell silent. I knew she was trying to hold back words, and feeling reluctant to let desire take the best of her consciousness.

“Imagine.” She stared at the ceiling. “Imagine if the three rats could talk to each other. If the rat in the second box told the one in the first box that the psychologists doing the experiment were devils, would the rat in the first box believe in it? And if the third rat told the first rat that it felt depressed because of the actions of the psychologists, would the first rat believe in it?”

“I guess not.”

“And imagine. If there were 90 rats in the first cage and only 10 rats in the third cage and they talk to each other afterward, would the 90 rats believe in the 10 rat’s words that the psychologists’ actions caused their depression?”

“The social effect.”

“Indeed. They believe only in what they think is true. They think they know, so they refuse to listen. But they don’t know. They’re not the third rats. Just because they have more people does not mean that they could speak for the rest.”

I squeezed my brain to understand what she was implying but failed to do so.

She stood up and returned to her desk to finish her schoolwork, and I left, still pondering what that sentence meant:

“They’re not the third rats.”

Who were the “they”?

V

When I returned to the police station, Yuan had more news for me. The body was found, at the estuary of the Jinghang Canal, and the coroner reported remnants of sleeping pills in her stomach, but she took far fewer pills than what was anticipated to be left in her apartment that night.

“Was it possible that Mrs. Lai took more pills than what the doctor ordered every night? That would make the number exactly correct.”

If Mrs. Lai took twice as many pills every night after she received her last delivery, the remnants of pills in the apartment on the night of July 4 would match the pills found in her stomach.

And at that I knew, I knew everything. I have been pointing my suspicion at Mr. Shyu throughout the investigation, but right now another suspect seemed to emerge from the mist.

I asked Yuan to check one last item.

VI

The pills along with Lini's words revealed the truth to me.

Lini was implying that she herself was the third rat, that no one believed in her. What did no one believe her in? That her mother was an emotionally unstable lunatic in front of her, of course. Lini could not tell whether pressing the button meant praise or destruction. 

Mrs. Lai took sleeping pills because of anxiety, but her work and love life were both stable and peaceful. None of her colleagues noticed her anxiety, and most of them liked her as a friend. It was likely that she suffered from Smiling Depression, a type of psychological illness that involves appearing to be joyful and friendly to others, but suffering from depression when alone or with close family members. 

Lini’s allegory was proof that she was never joking when telling Miss Luo that her mother was giving her pressure, but her sister did not believe in it. If I remember correctly, her exact words were “it is impossible, our mother, such a gentle figure in my memory, so I thought it was a joke”.  Since Miss Luo left home for boarding school at the age of 14, she was not as close to Mrs. Lai as Lini, so it was reasonable that Mrs. Lai did not appear depressed in front of Miss Luo. 

The source of Mrs. Lai's depression might have to do with the social effect theory that Lini mentioned. Could Mrs. Lai also be the third rat? The 90 first rats represented the adults of the world, such as my dear assistant Yuan, mother of a 12-year-old, and Mr. Shyu, those who believed that it was normal for children to work until midnight and not have any time to themselves. These adults had not suffered in their childhood what the children nowadays were suffering. And these first rats determined what was “normal” for a society. But they did not represent the third rats’ voice, because they were not the third rats, and they did not listen either. If Mrs. Lai was the third rat, as in she sometimes believed that stress was normal for children nowadays, but other times she wanted Lini to relax and do the things she liked, then this would connect with Lini's confusion about whether to press the button or not. Thus Mrs. Lai's depression might come from this inner conflict between her individual characteristic of being gentle and the social demand for a depressive parent, and this conflict makes her emotions unpredictable. Additionally, because back in Miss Luo's time, the first-rat situation was not as fierce, so Mrs. Lai never suffered from depression when raising Miss Luo, so Miss Luo had the stereotype of having a gentle and caring mother all the time.

On the evening of July 4, when Mrs. Lai "tutored" Lini’s homework, it is likely that Mrs. Lai was actually casting electric shocks upon Lini for pressing the button, and Mr. Shyu heard it. He knew Mrs. Lai was stressing Lini out, but he thought it was normal, so he did not interfere. But certain things in that conversation crushed Lini’s final heart of a child to pieces and made Lini desire the death of her own mother for the destruction. She stole all the remaining pills in the medicine drawer and gave them to Mrs. Lai without her noticing. Mrs. Lai died in the middle of the night, on her own bed beside her beloved husband Mr. Shyu.

At one point or another, possibly at midnight, when Lini was still working and not many people were on the streets, Mr. Shyu noticed that Mrs. Lai had died beside him on their bed. Since no one had been to the apartment at night, and Lini and Mrs. Lai had an argument just before bed, Mr. Shyu suspected Lini. In order to protect his daughter, Mr. Shyu aided Lini to carry the body away. And all the timelines that were provided to us by Mr. Shyu, such as when he first noticed that Mrs. Lai had disappeared, were lies. Lini did the killing, and Mr. Shyu was her accomplice.

The only reason why Mr. Shyu reported to the police was that he received the new package of sleeping pills on the morning of July 6, and he used them to his advantage. He thought that it was a seamless plan, and he could receive the heritage of her wife, so he decided to report the case. But he neglected what caused the tragedy in the first place—his daughter Lini, possibly suffering from depression due to loss of individual interest, pressure from family, distrust, and negligence. That was the final part of the whole story. I asked Yuan to contact doctors to seek to prove that it was Lini who took the missing pills, the same amount as her mother every night and that Lini was also suffering from insomnia due to anxiety.

And yes, Yuan got the proof I needed to complete the story.

She stood in awe under Miss Luo’s apartment, staring at a thin piece of cloth draped upon a pool of blood on the ground.

For a second there, she told me afterward, the body of Lini looked surprisingly similar to her own 12-year-old son.