I'm not a genius detective

Chapter 133 Determining the Source of Cyanide

The next day.

The two investigation teams split up. Han Ling and Tong Feng went to check the call records, while Zhang Yandong and Yang Hui went to Qingchang University to meet with university leaders to coordinate the investigation of the laboratory.

The investigation of the laboratory involved leaders and staff in multiple positions, including the laboratory director, drug administrator, security personnel, and the school's safety officer, each with their own set of procedures.

Zhang Yandong and Yang Hui only need to assist and supervise from the sidelines.

A student at Qingchang University is involved in a criminal case, and the police suspect that cyanide has been lost from the laboratory. This is a very big deal for the university leadership, and once verified, many people will be punished.

In the future, there will be significant changes in the management of hazardous chemicals. The current regulations are already very strict, and they will become even stricter in the event of an accident.

At 10 a.m., Han Ling and Tong Feng obtained the call records from the operator and then drove to Qingchang University.

On the way, Han Ling carefully checked Ren Yi's call records and compared them with the contact notes printed out on Ren Yi's phone. Within the past six months, no one was found to be outside the scope of the police investigation.

Her father, Lü Zhanpeng, Du Juncai, her dormitory classmates, her graduate advisor... these are all people Ren Yi frequently contacts.

"Have you found anything?" Tong Feng, who was driving, asked.

Han Ling shook her head: "No, he looks pretty normal."

Tong Feng: "Then...the problem lies with Lü Zhanpeng? Or with Ren Yi's mother?"

Han Ling put away the documents: "Let's wait for the results of other people's investigations. Let's find out the source of the cyanide first. Anyway, it either came from Lü Zhanpeng's company or from Qingchang University."

Currently, it seems most likely that the person is from Qingchang University. If Ren Yi is aware of this, she will most likely participate as well.

During their casual conversation, they arrived at Qingchang University, where they met up with Zhang Yandong and Yang Hui. At this time, the school's investigation into the laboratory had begun, all related courses were suspended, and Ren Yi's classmates and tutors were summoned.

They didn't know what had happened, only that there had been a problem with the laboratory's handling of cyanide, and that it was related to Ren Yi.

Even the criminal police have come; it's likely that this has led to some unpleasant consequences.

The heads of each position were very experienced, and after discussion, they launched a retrospective investigation targeting three aspects.

First, a standard product warehouse and a cabinet for highly toxic chemicals.

These two locations are managed by two people with two locks, and detailed records and the supervisor's signature are required for collection.

Second, the raw materials for a specific reaction.

Third, the prepared solution.

Zhang Yandong shared his opinion, putting himself in Ren Yi's shoes: "If I were Ren Yi, what methods would I use to obtain cyanide?"

This question is easy to answer; there are only two possibilities: directly obtaining it by exploiting management loopholes, or creating it yourself using professional knowledge.

“Ren Yi probably doesn’t have the extraction capabilities.” Facing the lab director and numerous school leaders, Ren Yi’s graduate advisor was very proactive in stating his judgment: “There are two types of extraction: biological extraction and direct extraction from cyanide-containing compounds. Biological extraction is extremely difficult, and the process of extracting from cyanide-containing compounds is cumbersome and too dangerous. It cannot be secretly implemented in the school.”

After listening to the professor's words, the lab director asked, "So, the only way is to exploit vulnerabilities to steal it, is that right?"

The tutor nodded: "I think so."

Since the criminal police from the Public Security Bureau have arrived, they basically assume that cyanide has indeed been lost, and that Ren Yi was the one who stole it.

Without solid leads, the police wouldn't have come to the school and made such a big fuss about investigating.

"What methods are there?" Zhang Yandong asked.

The graduate advisor pondered for a moment, then subconsciously glanced at the students present, wondering if it was inappropriate to "teach" how to steal chemicals in front of so many people.

Zhang Yandong could tell what the other person was thinking, and said, "It's okay, just say what needs to be said. This will help the school manage hazardous chemicals and prevent similar incidents from happening in the future."

Seeing the school leaders nod, the tutor then spoke up: "Three solutions."

First, use the "ant-like" method: in experiments that require the use of cyanide, weigh a little more than needed each time. For example, if the experiment requires 100 mg, apply for 120 mg. The extra 20 mg can be secretly transferred away with weighing paper or a microcentrifuge tube when no one is watching. By accumulating this over time, a considerable amount can be obtained.

The second method involves waste recycling. They falsely claim that a certain cyanide reagent or solution has deteriorated, become damp, or become contaminated, and apply for disposal according to the hazardous waste process. During the process of handling the waste liquid, they switch it with a similar-looking substitute.

Third, exaggerating the amount of material used. This method can obtain a large amount of cyanide in one go, but the conditions are quite demanding, requiring independent experiments, and it bypasses my and the lab's verification.

Everyone looked at the police officers from the Public Security Bureau.

All three methods involve the thief's subjective actions and have nothing to do with the school's management.

No matter how strict the management, someone will always find loopholes in the rules, which is difficult to prevent unless a camera is installed on every participant, even filming them going to the toilet, which is unrealistic.

Han Ling asked, "Which method is easier for students to implement?"

Mentor: "The first method is to acquire only a little bit each time."

Han Ling nodded: "Then let's investigate. Carefully review all of Ren Yi's experimental records. We need evidence to prove that Ren Yi had problems with the use of cyanide."

The lethal dose of cyanide for adults is approximately 50 milligrams. If only a small amount is taken each time, Ren Yi would need to make multiple trips.

The more times you do it, the more problems you encounter.

"it is good."

The supervisor nodded and immediately went to find Ren Yi's lab records. She didn't want to get involved in a criminal case or be punished by the school for this. Being proactive was always a good thing; maybe she could "redeem herself through meritorious service." The investigation into the lab continued into the afternoon, and the final results were in.

something wrong.

The problem lies in the experimental records; the data is incorrect.

By calculating the theoretical and actual usage, it was found that Ren Yi's requisition amount was indeed inflated. Each time, it was controlled within 5 milligrams and disguised as normal loss.

It's hard to detect if you don't check regularly.

It's too easy for the experimenter to tamper with the experiment; there's always a way.

Han Ling and the others didn't understand the details, nor did they need to. They only needed to know the result: Ren Yi had taken advantage of the experiment to steal cyanide multiple times, and the total amount had reached a level that could be fatal.

The investigation results were immediately reported to the special task force command center, and Ji Bowei interrogated Ren Yi again.

"You're a chemistry graduate student, more professional in this area than we are. You should know whether your actions can be found out by the school. I won't go into things like the amount taken or the experimental records. Your advisor, the lab director, and the safety officer have all participated in the investigation. I'll just ask you one question: what did you do with the cyanide you took?"

Ren Yi lowered her head slightly and remained silent, seemingly acquiescing.

Ji Bowen wasn't bluffing her. As a graduate student, she knew perfectly well whether the school could find out and how they would find out, so there was no point in making excuses.

“Silence won’t solve anything,” Ji Bowen continued. “Du Juncai died of cyanide poisoning. You stole cyanide from the lab, and you had a motive. Do you really want to keep dragging this out?”

Ren Yidao said: "I admit to stealing cyanide, but I did not kill Du Juncai. According to the law, stealing highly toxic substances is punishable by administrative detention. I admit it."

As for what I did with the stolen cyanide, that's my privacy. Unless it caused any adverse consequences, I don't have to answer.

At this point, both sides have essentially revealed their cards.

From Ren Yi's perspective, I know the police have identified him as a suspect in the murder, but you have no evidence, so I don't admit it.

From a police perspective, I know you were involved in the murder, and I also know your stubbornness—you won't admit it until you're faced with the consequences.

Without new clues and evidence, the situation will remain deadlocked.

The direction is correct.

Ren Yi participated in the poisoning of Du Juncai, but only provided the tools for the crime; the actual perpetrator was someone else.

To accurately poison someone's home, one would need a key and a clear understanding of Du Juncai's lifestyle. Given Lü Zhanpeng's premeditated murder plan and other suspicious behavior, Lü Zhanpeng should also be involved.

Pan Xia's inexplicable entry and exit from the community through the broken fence, coupled with her lying, suggests that even if she wasn't an accomplice, she was very likely someone who knew about the situation.

These three people should be interrogated continuously, and it will be enough if just one of them confesses.

The task force plans to use Pan Xia as a breakthrough point.

The interrogation continued, the external investigations continued, and everyone worked together to advance the case.

three days later.

Ji Bowei convened the Nth meeting to summarize the current investigation results and discuss future investigation directions.

The interrogation remains stalled.

Whether it was Ren Yi, Lü Zhanpeng, or Pan Xia, they all insisted that Du Juncai's death had nothing to do with them. Even when the interrogators tried to appeal to Pan Xia's emotions and clearly told her son what consequences he would face, they still couldn't break through the mother's psychological defenses.

The peripheral investigation has not yet found any new suspicious persons.

“Pan Xia is not right; she doesn’t fit her persona,” Hu Lihui said at the meeting. “It’s one thing for Lü Zhanpeng and Ren Yi to be different, but Pan Xia is a middle-aged woman. Her mental fortitude shouldn’t be this strong. Someone must have clearly informed her of the stakes.”

To be honest, Lü Zhanpeng will be prosecuted for murder.

If he doesn't tell the truth, Lü Zhanpeng is very likely to be acquitted.

The difference between those above and below is still quite large. As long as one is confident in their methods, keeping silent is the best option.

Indeed, the task force has been investigating for so many days, but still has no evidence to prove that Lü Zhanpeng is suspected of murder. The longer it drags on, the greater Pan Xia's expectations and confidence will become.

Fang Zhou said, "Another possibility is that the person who poisoned the house was Pan Xia. As long as she doesn't talk, her son will be safe, so she was able to endure the interrogation. However, judging from the footprint analysis of the technical squadron, the person who entered the house to poison the house should be a man."

The technical team has re-examined the crime scene multiple times and conducted in-depth footprint analysis on all the footprints at the scene, and finally determined that the overlapping new footprints came from Lü Zhanpeng's shoes.

Judging from the size of Pan Xia's feet, the size of Lü Zhanpeng's shoes, the pressure of the footprints, and the distance of the gait, Pan Xia did not commit the crime while wearing her son's shoes.

On the afternoon of the incident, Lü Zhanpeng remained at the branch office.

So there must be a fourth person who wore Lü Zhanpeng's shoes.

……

P.S.: Chapter 2 will be tonight. There are still a thousand words left. I'm experiencing a bit of writer's block, but I'll write it slowly.

My drafts have run out recently, so my update schedule has been a bit inconsistent lately. I'll try to save up some more in the next few days and keep the update schedule consistent at 6 PM every day.

I won't forget what I owe you, even if it's past midnight.

(End of this chapter)