Chapter 2087: Chapter 1792: New Chemical Compound

Everyone got into the car, followed by a brief silence.

Zhaxi spoke first, "What if Professor Zhou synthesized those organic phosphorus compounds himself? Then they would only exist in Professor Zhou’s laboratory, and the killer might have taken them from there."

Yang Ping looked at him with a smile on his face, a smile that was fleeting.

"You’re starting to think like a detective," Yang Ping said, "but you missed a critical question."

Zhaxi asked, "What?"

Yang Ping said, "If those organic phosphorus compounds were synthesized by Professor Zhou himself, how did the killer know about their existence? How did the killer obtain them? And how did the killer know which books Professor Zhou would look through?"

"The answers to these questions lead in one direction: the killer must be someone close to Professor Zhou, someone who can access his laboratory, know his research content, and be familiar with his reading habits. Furthermore, this person must know which books are in Professor Zhou’s study, know which books he would consult, and have access to them."

Zhaxi’s heart raced: "Are you suggesting it’s Li Xiong?"

Yang Ping shook his head, "I’m not saying who it is, I’m just listing conditions; there may be more than one person who fits these criteria."

Zhaxi’s mind buzzed. Li Xiong? That seemingly gentle and cultured young lecturer? He had been with Professor Zhou for twelve years, accessed his laboratory, understood his research content, and knew his reading habits. Plus, he had helped Professor Zhou buy toluene, and those two bottles of toluene might have been used to dissolve the organic phosphorus.

But what was the motive? What motive did Li Xiong have?

Officer Yu, sitting in the passenger seat, turned his head: "I need to investigate several matters when I go back. First, check Chen Wei’s Vid Pharmaceutical Company. What organic phosphorus products do they produce, and do any relate to phosphorus poisoning? Second, review the experiment log in Professor Zhou’s laboratory to see if we can find the ’attachment.’ Third, investigate Li Xiong’s background, his family, financial status, and interpersonal relationships. Fourth, examine the details of Professor Zhou’s threat letter to see if we can find more clues."

Back at Sanbo Research Institute, Yang Ping and Zhaxi sat down, and Yang Ping said, "Zhaxi, do you know what the biggest similarity is between clinical diagnosis and detective work?"

Zhaxi thought for a moment and said, "Isn’t it finding answers based on clues?"

Yang Ping shook his head, "Yes, but there’s also often the use of elimination. You eliminate all impossibilities, and what’s left, however improbable, is likely the answer. But before eliminating, you must list all possibilities. Missing one possibility might mean missing the truth."

He got off the car, walked a few steps, then turned back and said, "Don’t talk about today’s events with anyone, including other trainees."

Zhaxi nodded.

In the evening, Zhaxi finally found some free time. He began checking Vid Pharmaceutical Company’s product catalog. The company’s website was professionally done, with clear product categories: chiral ligands, chiral catalysts, and chiral intermediates. In the chiral ligand directory, he saw over a dozen organic phosphorus compound products with long names such as "(R)-BINAP," "(S)-Segphos," "DIPAMP," none of which he recognized.

He opened PubMed and started researching the toxicity information of these organic phosphorus compounds. Most had no explicit toxicity data, with only a few papers mentioning their synthetic intermediates had potential neurotoxicity. He searched for two hours and found nothing useful.

Then he began examining Professor Zhou’s experiment log. This was even harder; he had no physical object, only memory. He remembered the log read "Experiment Objective: Synthesize a new chiral organic phosphorus ligand. References: self-designed." If this was a new compound, it might not have any toxicity data, nor be listed in any toxic substance database.

He thought of a possibility: if the killer used this new organic phosphorus compound, routine toxicology screenings wouldn’t detect it. This was why Dr. Yuan and his team had delayed results.

He noted down this idea and started investigating Li Xiong’s background. This was relatively easier; Nandu University’s official website had faculty information. Li Xiong, male, born in 1988, lecturer, master’s mentor. Research field: asymmetric catalytic synthesis. Hosted a National Natural Science Foundation youth project, published 12 SCI papers. Family situation: married, one child, five years old. No more information available.

He researched all afternoon, accumulating a desk full of materials, but genuinely valuable clues were scarce.

The next morning, after completing surgery, Zhaxi went to report to Yang Ping at noon. Yang Ping was in the office reading an English paper, a cup of cooled tea beside him.

Zhaxi briefly reported the afternoon findings. Yang Ping listened, paused, then said, "You missed a crucial item."

Zhaxi was taken aback, "What?"

Yang Ping said, "Did you research the content of Professor Zhou’s threat letter?"

Zhaxi lowered his head, "Not yet."

Yang Ping didn’t criticize him but instead took a piece of paper from the drawer and handed it to him. Zhaxi looked; it was a copy of the threat letter. The letter was printed on ordinary A4 paper in standard Song font, and its content was brief: 𝓯𝓻𝒆𝙚𝒘𝓮𝙗𝓷𝒐𝓿𝙚𝒍.𝙘𝓸𝙢

"Professor Zhou, do you think no one knows about what happened thirty years ago? The truth will not be hidden forever, your time is running out."

Zhaxi read it twice but found nothing special. He lifted his head and looked at Yang Ping.