About twenty minutes later, Yang Ping closed the notebook and placed it on the table. He didn’t comment on Zhaxi’s speculation, but said something unexpected: "Get some sleep early tonight; tomorrow morning, go with me to Nandu University."

Zhaxi was momentarily stunned: "To Nandu University?"

Yang Ping nodded: "To meet someone, Professor Zhou’s students—not just Li Xiong. We need to understand Professor Zhou, his character, habits, interpersonal relationships, and what has happened in the last six months." He paused and looked at Zhaxi, "These speculations you’ve written, they’re logically sound. But being logically sound doesn’t mean they’re factually true; we need more evidence."

"Zhaxi, we could have simply provided some clinical knowledge consultation to Dr. Yuan, but why am I letting you deeply involve in this matter? Because I want you to know, for researchers, curiosity is crucial. Protect your curiosity; never stifle it. Follow it, and you’ll tirelessly solve one mystery after another. Do this in your studies, and you’ll grow quickly."

Zhaxi nodded, understanding Yang Ping’s meaning.

At eight on Saturday morning, Yang Ping and Zhaxi got into Dr. Yuan’s car. This time, the driver was Old Yu, an old detective brought by Dr. Yuan, responsible for the case. Dr. Yuan sat in the front passenger seat, looking more solemn than in previous days. Zhaxi noticed he held a new document in his hand, with "Confidential" printed on the cover.

"Dr. Yuan, any new discoveries?" Yang Ping asked.

Dr. Yuan handed the document over: "Last night, Old Yu conducted an overnight investigation into Professor Zhou’s social relations and found some interesting things." His tone was calm, but Zhaxi could sense the hidden tension.

Yang Ping opened the document, and Zhaxi leaned in to look together. The first page contained Professor Zhou’s personal information: Zhou Huaixin, male, 62 years old, Chemistry Professor at Nandu University, Doctoral Student Mentor, research focus on asymmetric catalytic synthesis. He once won the National Natural Science Second Prize and several provincial-level science and technology awards, published over 180 papers in domestic and international journals, trained 23 doctoral students, and 31 master’s students.

The second page started with his student list. Zhaxi glanced at the densely packed names, followed by graduation years, thesis titles, current work units. He saw Li Xiong’s name, who graduated with a doctorate in 2018, now teaching at the university, and managing the lab after Professor Zhou’s retirement.

Dr. Yuan’s voice came from the front: "Professor Zhou has many students, most of whom went to universities or institutes. A few went into industry, and all are doing well. But one person is quite special."

Yang Ping flipped to the third page. There, a name circled in red pen: Chen Wei, male, graduated with a doctorate in 2009, thesis title: "Design and Synthesis of Novel Chiral Phosphine Ligands and Their Application in Asymmetric Catalysis." Under the post-graduation direction was written: Entrepreneur, now Founder and Chairman of Vid Pharmaceutical Technology Co., Ltd.

"Chen Wei!" Yang Ping repeated the name.

Dr. Yuan said: "Yes, Chen Wei was one of Professor Zhou’s most outstanding early students. During his doctoral studies, he published two papers in JACS and one in Angewandte, quite outstanding achievements in organic chemistry. After graduation, he didn’t join academia but went into business, founded Vid Pharmaceutical, focusing on the synthesis and sale of pharmaceutical intermediates. The company grew significantly, now valued at over a billion."

Yang Ping continued reading, and the subsequent pages of the document detailed the relationship between Chen Wei and Professor Zhou. Zhaxi saw a few lines, and his heartbeat suddenly accelerated. "In the early stages of entrepreneurship, Chen Wei sought frequent technical support from Professor Zhou. Professor Zhou transferred some of his research group’s findings to Chen Wei’s company, and they signed a technology transfer agreement. In 2015, they had a dispute over technology transfer fees, Chen Wei sued Professor Zhou but later withdrew the lawsuit. Since then, their relationship deteriorated, with no further contact."

Yang Ping finished reading, closed the document, and stayed silent.

Xiao He at the front said: "Professor Yang, we also investigated the threatening letter Professor Zhou received a week before his death, but couldn’t trace the source."

This should have been Old Yu’s report, but perhaps he believed Dr. Yuan was more familiar with Professor Yang, so he asked Dr. Yuan to replace him.

Yang Ping’s eyes slightly squinted: "Chen Wei’s company, what products does it mainly make?"

Dr. Yuan replied: "Pharmaceutical intermediates, especially chiral pharmaceutical intermediates. We checked their product catalog, containing many organophosphorus compounds."

Yang Ping’s gaze flickered: "Organophosphorus?"

"Yes!" Dr. Yuan said, "Chiral organophosphorus compounds are commonly used ligands or catalysts in chiral drug synthesis. Chen Wei’s company has several products that are organophosphorus types."

Yang Ping didn’t speak further, leaned back in the seat, closed his eyes. Zhaxi knew he was pondering over something.

At Sanbo Research Institute, there’s a saying: no matter how difficult a case is, never fear when Professor Yang squints. Once Professor Yang closes his eyes to ponder, when he opens them, the problem solves itself.

Nandu University’s Chemistry Department’s main building is a grey-white structure built in the 1980s, showing its age. A large sycamore tree stands in front of the building, leaves turning yellow. Dr. Yuan parked the car downstairs, and the four of them got out, heading into the building.

Li Xiong was already waiting at the entrance. Today, he was wearing a dark blue shirt, looking more spirited than last time. He led them to the third floor and into a meeting room. The meeting room was small, with a long table, a dozen chairs, and a whiteboard on the wall.