Chapter 144: The Real Culpri (1/2)

We went outside and saw Cheng Yahui lying on the ground. He was crouched in a fetal position and was still conscious, but he was writhing and groaning in pain.

Xiaotao kicked him and said, “Get up! You’re trying to frame the police, aren’t you?”

“Wait,” I stopped her. “It looks like he’s been poisoned!”

I pulled up his eyelids and checked his pupils. They were contracted, and his eyes were bloodshot—these were clear signs of poisoning. But who could poison him? He’d been in police custody since morning!

I told Dali to quickly get some soapy water to induce Cheng Yahui to vomit. Suddenly, Cheng Yahui clutched at my wrist and with much effort told me, “My medicine… I left it in the interrogation room…”

Xiaotao ordered an officer to check the interrogation room immediately. He then returned a few minutes later with a bottle of medicine under the desk. It was labelled as tranquilizer. No one dared to give Cheng Yahui the medicine. What if it ended up causing his death? That would cause the police immense trouble. The safest thing to do right now was to induce vomiting.

But when Cheng Yahui saw the medicine, he almost frantically pleaded, “Give it to me… I’ll be in terrible pain if I don’t take it…”

“No,” Xiaotao refused. “We need to test it first.”

“No!” he yelled. His face was distorted by pain. “Give me! Now!”

I had a sudden epiphany of what was going on and grabbed the medicine from Xiaotao’s hand and stuffed it into his mouth.

“What are you doing, Song Yang?” Xiaotao was in utter shock.

“Don’t worry, this is the antidote!”

Less than a minute later, Cheng Yahui recovered.

“Terribly sorry for that,” he said. “I have neuralgia. If I don’t take this medicine every once in a while, the symptoms will appear.”

“Who prescribed this medicine for you?” I asked.

“I do it myself, of course,” he replied. “I’m a doctor after all.”

“But you’re a gynecologist,” I argued. “How would you know how to treat neuralgia?”

“Please!” Cheng Yahui laughed. “I’m a certified medical doctor! Why wouldn’t I understand such a simple disease?”

“Nevertheless,” I frowned, “could you please sit down and wait for a while? We’d have to do some testing.”

Cheng Yahui was hesitant, but there was nothing he could do. We asked for his urine samples and Bingxin tested both his urine and the medicine. After half an hour, Bingxin came out of the lab and announced, “I couldn’t identify the ingredients in the medicine, but I found traces of atropine poison in his urine sample.”

“It’s Yin and Yang poisoning!” I cried.

“What?” asked Xiaotao in confusion.

“It’s a poisoning technique that my ancestor recorded,” I explained. “You’d put two substances in two different food dishes. If someone ate only one of those, they’d be fine. It’s only when both are eaten that the poison would take effect. You can also do the opposite—by adding poison to one dish and the antidote in another. You could poison your guests by eating the same dishes with them and then save yourself by taking the antidote later.”

“That’s just like the synergistic and antagonistic effect that we learn in our toxicology class,” Bingxin remarked. “Sometimes two drugs can become poisonous when ingested together, or they can inhibit the other’s effects, meaning one drug might turn the other drug into a harmless substance.”

“We would’ve never figured this out if Cheng Yahui hadn’t collapsed here,” I said. “The murderer must’ve done this to Cheng Yahui, which means that the murderer is likely someone close to him!”

When I put it that way, everyone had the same person in mind—Qu Tingting!

We brought Cheng Yahui back into the interrogation room. He insisted again and again that he prescribed the medicine himself. Then I asked him, “Who gets the medicine for you?”

“Nurse Qu,” he answered.

“What is Nurse Qu’s educational background?” I asked.

“I don’t know,” he said. “Some nursing college, perhaps. I don’t talk to her much.”

Xiaotao waved her hand to let him leave. Everyone fell silent once he was gone. All of us had overlooked this blind spot. Qu Tingting was clearly the real culprit! Her motive was most likely jealousy.

“What are we waiting for?” Xiaotao suddenly shouted. “Let’s go catch the murderer!”

We hurried to the university hospital, but Qu Tingting was already gone. All we could do was to ask the head nurse to call her.

“Damn it!” cursed Xiaotao with frustration. “She must’ve run away when she saw Cheng Yahui getting arrested! She must’ve known that her whole plot would be exposed once Cheng Yahui was questioned.”

“Let’s go to the gynecology department,” I suggested.

We went into Cheng Yahui’s office. It was all neat and tidy except for a stack of papers on the desk. Xiaotao rummaged through the whole room and sighed, “There’s nothing here.”

“Wait!” I went to the desk, took a pencil, and smeared the whole piece of paper until a few lines of words gradually appeared.

“Dr. Cheng,” it said, “I must leave now. I will be gone for quite a long time. I prepared the medicine for you. Please remember to take it. It won’t be enough for long. When you run out, I will tell you the formula for the antidote if you come and see me. Also, I have something important to tell you…”

The words stopped after that. It seemed that Qu Tingting hesitated and tore off the paper at that point.