Criminal Investigation Notes
Criminal Investigation Notes: Extra 3


Over the next two days, the police made significant progress on the case, and Yu Yan received various testimonies and pieces of information.

This afternoon, Captain Li directly sent over the remaining documents.

Yu Yan looked at the testimonies, organizing the case details.

With the testimony of the witness at the entrance, the investigation proceeded smoothly.

The autopsy report confirmed that Zhou Bingyi’s time of death was between 6 PM and 8 PM in the evening, and she hadn’t eaten dinner.

The police quickly identified the individuals entering and leaving the premises through surveillance footage.

On that day, there were a total of three people entering and leaving Zhou Bingyi’s residence.

The first person was a 42-year-old cleaner named Xu Zhaoran, who did occasional cleaning work nearby. Zhou Bingyi mostly handled household chores herself, and Xu Zhaoran came over only occasionally, approximately once a month.

The second person was an elderly lady from the neighborhood committee in the area, surnamed Yu and named Yu Ran. She was 72 years old and an older resident. As a member of the neighborhood committee, she often visited the homes of elderly residents, providing them with subsidies and showing concern for their well-being.

The third person was Zhou Bingyi’s distant nephew, Zhou Wanglin, who was 33 years old. Although he had a wife and child, he was somewhat wayward and was fired from his job last year. He had been doing odd jobs since then.

The police summoned them for questioning one by one.

The testimonies were cross-referenced with the surveillance footage of their entries and exits from the residential area, creating a timeline of events for that day.

Around 4 PM that day, Zhou Bingyi called Xu Zhaoran to her residence for cleaning. At around 5 PM, Yu Ran arrived, and the two chatted for a while.

At 5:45 PM in the evening, Xu Zhaoran finished the cleaning, and after chatting with Yu Ran, they both left together.

Both Xu Zhaoran and Yu Ran stated that when they left, Zhou Bingyi seemed fine and there were no signs of anything unusual.

At 6 PM, Zhou Wanglin entered the residential area, and at 6:30 PM, he left hastily. According to the surveillance footage, he left while wearing his clothes inside out.

Zhou Wanglin had a strong suspicion against him. Captain Li questioned him overnight and finally extracted a confession of his crime.

Zhou Wanglin admitted to the process of killing his aunt, and the motive was the property owned by Zhou Bingyi.

Due to unemployment, his family of three lived crammed into a 30-square-meter apartment, and he had his eyes on this property.

Zhou Wanglin had visited Zhou Bingyi several times over the year, first offering to take care of her and later suggesting she move in with his family. Zhou Bingyi had consistently rejected him.

This time, Zhou Wanglin was persistent and even brought a document for transferring property ownership, hoping Zhou Bingyi would sign it.

Zhou Bingyi got angry, grabbed a fruit knife from the table, and tried to chase him away. However, during the struggle with Zhou Wanglin, she accidentally fell, and the knife pierced her own body.

Zhou Wanglin was terrified; he had blood splatters on him, so he turned his clothes inside out and rushed out in a panic.

Upon reading this, Yu Yan asked Captain Li, “Captain Li, what about the poison? Why isn’t the testimony mentioning the poison?”

In his view, the stabbing was just a surface issue. To find the real culprit, it was crucial to determine who had poisoned Zhou Bingyi.

Captain Li replied, “That part was only obtained this morning and is still being organized. Zhou Wanglin confessed that he bought a pack of sleeping pills from a rural medicine vendor and planned to put them in water for Zhou Bingyi to drink. He intended to use her unconscious state to press her fingerprints for transferring property.”

Yu Yan said, “Property transfer requires notarization…”

Captain Li interrupted, “He doesn’t know much about the law.”

Yu Yan frowned, “Moreover, Zhou Bingyi didn’t actually take the sleeping pills.”

If she had, even a small amount could be detected through blood tests. The autopsy report didn’t mention this.

Captain Li said, “Maybe the medicine vendor gave him the wrong pills. Rat poison is a white powder, right? It’s also possible that Zhou Wanglin had murder in mind all along and is now lying to get a lighter sentence.”

Seeing through his evasiveness, Yu Yan raised an eyebrow, “Is that so?”

Captain Li scratched his head in slight annoyance and admitted, “The guy keeps changing his story—first he said he saw her drink it, then he said he didn’t see it clearly, then he said he forgot. He’s not sure whether she actually drank it or not. We are still questioning him to get a definitive statement. But surely, this matter is connected to him. After this, it’s no longer for us detectives to judge. The court judge will decide based on his testimony.”

Yu Yan asked, “Are there any physical evidence? Can we prove what substance he gave Zhou Bingyi?”

Captain Li shook his head, “Zhou Wanglin said he got scared of leaving traces, so he poured the water and washed the cup.”

“Did you check the drain?” Yu Yan inquired, “What about the remaining medicine?”

“It’s been a few days; we didn’t find anything. The medicine is gone, and we heard the medicine vendor fled when they heard about the incident.”

Yu Yan said, “So, right now, we only have Zhou Wanglin’s confession?”

“Isn’t a confession enough? We interrogated him all night yesterday, and he finally admitted. He wouldn’t just admit to a murder he didn’t commit, right?” Captain Li frowned and asked Yu Yan, “Teacher Yu, I know you criminology folks tend to be suspicious, which sometimes helps solve cases. But other times, it makes simple matters overly complicated. In my view, this case was really done by Zhou Wanglin. The other two individuals are an elderly lady even older than Zhou Bingyi and a widow named Xianglin. They were close to Zhou Bingyi, you can even say they were her only friends. There were no grudges, no conflicts over property; how could it be them?”

Yu Yan noticed that Captain Li used an adjective, and he was slightly taken aback, “Xianglin?”

Captain Li nodded, “Yes, that woman is quite pitiable—both parents dead, husband dead, son and daughter dead as well. She’s like a star of misfortune. We asked her a few questions, and she cried for almost an hour. Plus, the regular customers of her business are now deceased… She’s quite distressed.”

Yu Yan asked, “Why isn’t this information in the testimonies I read?”

Captain Li sighed, then explained, “She cried for nearly an hour. If we wrote all that, the higher-ups would think we’d gone mad. Don’t worry, we’re following the procedure; there are audio recordings.”

Seeing Yu Yan’s silence, he continued, “Alright, alright, let’s go add this to the supplementary testimony. Yu Teacher, when would it be convenient for you to sign it?”

Captain Li was beginning to regret involving the Behavioral Analysis Unit; had he known it was this straightforward, he wouldn’t have brought them in.

After a case handled by the Behavioral Analysis Unit, Yu Yan’s signature was required to close the case.

If Yu Yan delayed for a few days, it would impact their case-solving efficiency.

After a moment of thought, Yu Yan said, “Captain Li, I’ll look over the case file again tonight and study it. If there are no issues, I’ll sign it for you by the end of the workday tomorrow.”

“Tomorrow…?” Captain Li sounded a bit discontent. It was only 3 PM now, and he had hoped to wrap things up today.

“What’s wrong? Are you in a hurry?” Yu Yan’s tone turned cold, and he raised his head, eyebrows slightly arched.

He was typically mild-mannered, but only in daily life. When it came to a case, he was meticulous. No one could fool him in that regard. Don’t even think about getting away with shoddy work in his presence.

Captain Li sensed a hint of sharpness in his tone, and his attempt to be assertive was stifled by Yu Yan’s expression.

He had heard rumors circulating

 in the department, especially among the older traditionalists who disliked new things. They saw Teacher Yu as a thorn in their side due to his good looks, accusing him of all sorts of things.

However, as he worked on the frontline, he had witnessed Yu Yan solving several cases himself. He knew that Yu Yan indeed had real skills and hadn’t just relied on flattering higher-ups to get his position.

After all, they were all in a collaborative department. If they truly provoked Yu Yan, it might end up complicating their work.

Thinking this, Captain Li suppressed his temper and decided not to offend him, “No, no, take your time. I can wait for a while.”

After saying that, Captain Li walked out of the room.

Yu Yan handed the documents to Yao Fei and softened his tone, “Go make a photocopy and then check the death records in nearby neighborhoods from the past three years.”

Yao Fei took the documents and replied with an “okay.” Then he asked, “Teacher, do you suspect this case is connected to an ‘Angel of Death’?”

Yu Yan asked back, “What do you think?”

Yao Fei lowered his head and thought for a moment, “It doesn’t seem like it. Most ‘Angels of Death’ target elderly people with reduced mobility. Zhou Bingyi doesn’t fit that profile. I know there have been cases recently where caregivers were tired of taking care of the elderly or where children hired someone to commit murder. However, this woman, Xu Zhaoran, is a cleaning worker, not a caregiver. There’s no profit in it for her, and the risk of getting caught is too high for her to randomly kill someone.”

“You’re considering the typical situation; you also need to consider atypical scenarios,” Yu Yan advised, “This kind of reasoning can easily lead to subjective assumptions. For now, stick to standard procedures and cautiously investigate these cases in parallel. Bring over the materials for now.”

Yao Fei acknowledged with a sound of agreement and went to communicate with the local sub-bureau.

At this point, Yu Yan was reminded of the Q group he had seen on Zhou Bingyi’s phone earlier. He tried to join the group but found that it was a closed group, not accepting outsider applications. The group had 36 members in total. The description stated that it was a daily check-in group.

Yu Yan contacted the cyber police to retrieve records. The group’s location was near the neighborhood, and it consisted solely of check-in posts. Looking at the profile pictures, he noticed that most were not anime characters, primarily featuring cats, dogs, and scenery, suggesting that the group’s members were likely older.

Around 5 PM, the sub-bureau sent over the data and files. Yao Fei initially screened them, removing cases with apparent causes and accidents, and handed a few cases without obvious causes over to Yu Yan.

As Yu Yan reviewed the cases, Yao Fei seemed to be idle. Observing the time, he shut down his computer and reminded Yu Yan, “Teacher Yu, it’s time to clock off.”

Yu Yan responded with an “oh” and said, “I’ll work a little longer. I’ll head home a bit later tonight.”

Yao Fei opened a food delivery app, asking, “Should I order food for you?”

Yu Yan shook his head, “I’m going to a relative’s place for dinner later.” He noticed that Yao Fei didn’t leave and asked, “Why aren’t you going off duty?”

Yao Fei propped his legs up on a nearby stool, “I’ll be alone at home too. At least here, there’s air conditioning.”

Yu Yan didn’t pay him much mind, continuing to review the materials. He was engrossed in them and momentarily lost track of time.

Yao Fei probably received his food delivery; he left to collect it.

Yu Yan glanced at his phone, noticing a notification with “99+” messages in a Q group.

It was a local police officers’ group; he had forgotten when he had joined it. It had been stored in his group assistant, and today it had popped up.

While the group consisted of police officers, there weren’t many leaders present. Usually, they gossiped and chatted in the group, shared some information, and occasionally organized gaming sessions together.

At this moment, a member named “Jin Dafu” was expressing his anger.

Because this group wasn’t an official work group, the group name was diverse and varied.

Jin Dafu was venting, “@Everyone, look at you young ones, don’t you remember that you’re police officers? Naming yourselves with these creative names, like ‘Veteran driver, take me for a ride,’ ‘Linzi Small Fatty,’ ‘Bai Cai Part-Timer.’ Do you still have any decency to be police officers? Is there something wrong with your thinking?!”

This person was new, and no one recognized him in the group.

Someone asked, “Who are you? Do you live by the sea? You’re really nitpicking.”

“Yeah, our leaders haven’t said anything. Why are you picking faults?”

“We’re exhausted enough completing tasks during work hours. Why can’t we have fun with our usernames after work?”

“Do we need to have strict rules about nicknames for private accounts? It’s not a work account.”

The masses were quite angry, and an account named “Flying Maotai” even posted a mocking emoji.

Jin Dafu persisted, “I’m Jin Da!”

For a moment, the group fell silent. Everyone knew that this was Jin Deputy Director of the General Administration, and recently, he had been cracking down on discipline and ethics. Today, he was incognito in the group.

“All of you, don’t think that a private account in the group is beyond rules. If your names are inappropriate, or if you usually post all kinds of unrelated pictures, correct yourselves immediately. For serious cases, you’ll need to write a self-critique.” Deputy Director Jin continued to vent, “And you, what’s with ‘Flying Maotai’? You seem like the police force has been corrupted!”

Flying Maotai retorted, “I’m just picking a name for fun. Old leader, you’ve enjoyed quite a few drinks too, right?”

The group fell into silence again.

Deputy Director Jin initially wanted to playfully nitpick and flex his authority by changing a few names. Yet, this person directly pushed back.

Deputy Director Jin said in astonishment, “Unbelievable! Which sub-bureau are you from? Which department?!”

The group fell even quieter.

Flying Maotai didn’t reply.

After a while, someone timidly spoke up, “N-No… don’t know…”

“We don’t recognize them…”

“They’re not from our Third Sub-bureau.”

“There are hundreds of people in this group. Maybe they’re not even from the police department?”

“What about the group owner? Wasn’t it said that entry into the group requires verification?”

Flying Maotai remained silent for a moment, then directly sent a picture. The photo was taken at an unknown time; Deputy Director Jin’s face was flushed red, and his image was utterly compromised. Unfortunately, right next to him was a bottle of Maotai.


The person responsible for maintaining discipline had suddenly been exposed.

It turned out that this person didn’t directly confront them earlier; he was holding back his trump card.

Soon after, someone realized, “Bro, you’re tough enough!”


“Who is the person in the photo…”

Deputy Director Jin remained silent for a moment, filled with powerless rage, “You little brat, just wait till I catch you!”

He had just typed that message.

Someone shouted, “Protect the hero!”

“What’s there to fear? The law doesn’t punish the masses!”

“I’ve been annoyed by this arrogant old man for a long time. If he has the guts, he should expel all of us!”

Then, someone realized, “Group owner, quick, run!”

“Disband the group! Disband!”

And then the group really disbanded.

Yu Yan didn’t use QQ very often. If it weren’t for checking Zhou Bingyi’s information today, he wouldn’t have opened this app for a long time. Unexpectedly, he was greeted by this scene.

He thought about it and found that Flying Maotai’s profile picture looked a bit familiar. He checked his friends list…

Then he saw Yao Fei entering with takeaway in one hand and his phone in the other.

He held a cigarette in his mouth, pursing his thin lips, not lighting it.

Yu Yan: “…”

Yao Fei: “…”

Yu Yan: “Just now… wasn’t that you in the group?”

Yao Fei, cigarette dangling from his mouth, mumbled unclearly, “Don’t worry, Teacher, there are hundreds of people in the group, tens of thousands if you consider all the sub-bureaus. My alternate account can’t be traced.”

To avoid worrying Yu Yan, he added, “Besides, I didn’t say anything too bad. Everything I said was true. The picture was taken on a whim. If he dares to do something, I’ll dare to expose him. I even have a few more pictures; I’ll send them to the disciplinary commission later.”

Yu Yan massaged his forehead, “For safety’s sake, why don’t you change your name first?”

Yao Fei’s lips curled into a smile, “I think my name is pretty good? Dignified and with a hint of aromatic flavor.”

Yu Yan: “…”

Seeing Yu Yan looking at him with a slightly distressed expression, Yao Fei yielded, “Then, what should I change it to? Flying Little Policewoman?”

Yu Yan sighed, lowering his head, “Can’t you pick a more discreet and normal name?”

As the two were talking, the office suddenly went dark, as if the power had gone out. The lights and computers went off, even the air conditioning stopped.

The surroundings suddenly fell quiet.

The room was pitch black, only illuminated by the light of phones and a faint moonlight seeping through the curtains.

Yao Fei looked down at Yu Yan, and a ray of moonlight happened to shine down, falling on his face.

In the midst of complete darkness, this person was illuminated. The light was faint, silver-white, as if emitting a holy radiance.

Time seemed to stand still.

“Moonlight…” Yao Fei unconsciously uttered the word, the cigarette he held falling to the ground.

Tonight’s moonlight was so beautiful.

“What?” Yu Yan was bewildered by the sudden power outage, not grasping Yao Fei’s meaning.

Someone switched the circuit breaker back on; the power outage lasted just over thirty seconds. The darkness disappeared in an instant, the lights in the room came back on, and the air conditioning buzzed to life.

The world was illuminated once again.

However, Yao Fei was still recalling the scene he had seen during the blackout.

Yu Yan asked, “What were you saying just now?”

Yao Fei wasn’t in a rush to reply. He crouched down, picked up the cigarette he had dropped, and pinched it between his fingers. He brought it under his nose and took a sniff, somewhat reluctant to part with it. Then he flicked the ashes, throwing the cigarette into the trash.

Yao Fei raised his pair of captivating eyes to look at Yu Yan and said, “Teacher, I’ve figured out a new name for myself. Call me Moonlight.”


Yao Fei is allergic to authority lmao. Well, except Yu Yan’s. He would probably do anything his Teacher asks without hesitation.


Certified member of the IIO(International Introverts Organization), PhD holder in Overthinking and Ghosting, Spokesperson for BOBAH(Benefits of Being a Homebody), Founder of SFA(Salted Fish Association), Brand Ambassador for Couch Potato fall line Pajama set.

1 comment
  1. Iwansubsplz has spoken 9 months ago

    im sad that Yu Yan died… can you imagine seeing Yao Fei and Yu Yan now 🥹


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