Chapter 1

In my first year as a criminal investigator, I encountered a murder case I would never forget.

The suspect's intricate planning and ingenious method would send shock waves through judicial circles around the world.

At the time of the crime, he had a perfect alibi.

As our investigation progressed, the pieces fell into place.

Everyone believed he was the killer.

Yet we could find no direct evidence to prove it.

This was the monkshood murder case—hailed as the most perfect crime in history.

I remember the date clearly: April 1, 2007.

It was April Fools' Day, and my mentor, Yan Hao—a stern man who rarely smiled—was grinning as he offered to set me up with a girlfriend.

As if I was falling for that.

I was on night duty. It was raining outside, and I thought things would probably stay quiet. I was about to put my head down on the desk for a nap.

Suddenly, the duty-room door flew open.

A woman stumbled in, soaked to the skin and visibly terrified.

I stood and tried to calm her. I draped a light blanket over her shoulders and poured her a cup of hot water.

After a while, she regained a little composure.

She stared at me.

“You have to get justice for my best friend, Li Zihan.”

Following procedure, I switched on the audio and video recording equipment.

Then she told me what had happened.

The woman's name was Cheng Sisi. That afternoon, she had traveled from Mingzhou to Binhai on holiday with her best friend Li Zihan and Li's fiancé, Zhang Jun.

They had arrived at the hotel later than expected. The weather was bad too, so Li Zihan suggested resting that evening and going out the next day.

At that point, I interrupted.

“Forgive my curiosity, but weren't they a couple going on holiday together? Wasn't it a little awkward for you to go along?”

“I wasn't planning to,” Cheng Sisi explained. “Zihan insisted. She and Zhang Jun had only known each other for two months when they impulsively registered their marriage.”

“But dating is one thing. Marriage is another. Zihan regretted rushing into it, so she suggested a holiday to see whether they were really suited to living together.”

“If they weren't, she wanted to end things quickly. With me there, at least she'd have someone to back her up.”

I nodded and asked her to continue, keeping to the important points.

Her eyes suddenly reddened. She covered her face and began to sob, her voice breaking.

“But... she just... died!”

My heart lurched.

“How? Where's her body?”

“I don't know how she died. She's... she's in the morgue at the Municipal People's Hospital. And I can't reach Zhang Jun, no matter what I do.”

She seized my hand.

“It has to be Zhang Jun. He killed her, then ran away because he was afraid of being caught.”

This was serious. I went straight to the rest room to wake Yan Hao.

After hearing a summary, he turned to Cheng Sisi.

“Why would Zhang Jun kill his fiancée? And why are you so certain he's the killer?”

“A woman's intuition.”

She answered without hesitation.

For a moment, I had nothing to say.

Intuition?

Still, there were certainly suspicious circumstances.

The fiancée was dead.

The fiancé was missing.

Just then, Cheng Sisi cried out.

“The station! That's right—the station! An hour before it happened, Zhang Jun said his company had called. Something urgent had come up, and he had to go back.”

My mentor sensed that something was wrong.

He suggested we split up. I would look for Zhang Jun at the railway station while he went to the hospital to speak to the doctor who had treated Li Zihan.

Visibility was poor in the rain. I switched on the police lights and drove fast.

As I drove, I thought it through.

According to Cheng Sisi, about an hour had passed since Li Zihan collapsed.

Zhang Jun had left for the station an hour before that. He had already had a two-hour head start.

If he was the killer, he might be long gone.

I decided to try my luck anyway.

In 2007, train tickets were not yet sold under a real-name system. Finding one man in a crowded station would not be easy.

I went straight to the announcements office, intending to have his name called over the loudspeakers.

Looking back, I was an idiot.

If Zhang Jun was the killer, wouldn't I be warning him?

“Passenger announcement. Would a passenger named Zhang Jun please report to the announcements office immediately?”

Fortunately, he appeared ten minutes later.

He stopped short when he entered and saw me in uniform.

“Are you looking for me? What's this about—”

Before he could finish, I took him to the car and drove straight to the People's Hospital.

On the way, I told him his fiancée was dead.

He stared, shaking his head over and over, saying it was impossible.

Then he grew restless, wringing his hands, before burying his face between his knees and sobbing.

I watched him carefully in the rearview mirror. Nothing about his behavior seemed unusual.

Except for one thing.

After learning that his fiancée had died, he did not immediately ask how.

I asked why his phone was off. He said the battery had died.

I was driving and had no time to check.

But he seemed desperate to prove it. He held the phone up in front of me and pressed the power button. Only when I nodded did he put it away.

At the hospital, I found Yan Hao and Cheng Sisi outside an operating room on the sixth floor.

A red light above the door read EMERGENCY TREATMENT IN PROGRESS.

Puzzled, I pointed at the door.

“Li Zihan isn't dead? They're still trying to save her?”

My mentor shook his head.

“The doctor who treated her before she died is operating on another patient. We'll have to wait for him to come out.”

We had barely exchanged a few words when an argument broke out nearby.

Cheng Sisi had grabbed Zhang Jun's arm and was shaking it furiously.

“You murderer! You monster! What did Zihan ever do to you? Tell me!”

“I didn't do anything! I loved her. Why would I hurt her? Don't make wild accusations in front of the police!”

“Enough! Where do you think you are?”

My mentor's shout cut across them.

He frowned, his gaze cold.

I hurried to pull Cheng Sisi away, then pointed to a seat farther along the corridor.

“Zhang Jun, sit over there for a moment.”

Half an hour later, the operating-room light turned green.

The surgeon, Dr. Zhao, came out. My mentor and I went straight over.

After we explained why we were there, he removed his mask.

“She was already in a critical condition on arrival. Her heart and lungs had almost stopped functioning. The main symptoms were difficulty breathing, an irregular heartbeat, and a high temperature. They were consistent with a myocardial infarction.”

“Could she have been murdered?” I asked. “Poisoned, for instance?”

Dr. Zhao shook his head.

“It didn't look like it. A more definite answer would require a forensic autopsy.”

We thanked him and returned to the criminal investigation unit.

Under the rules, without direct evidence that Zhang Jun had committed murder, we could hold him for no more than twenty-four hours.

At that stage, all we had were a few suspicious details.

To clarify matters, my mentor and I took another, more detailed statement from Cheng Sisi.

Again, we found nothing unusual.

My mentor stood and sighed.

“No evidence. No motive. We can't open a case. That's that.”

Suddenly, Cheng Sisi slapped the table.

“I remember! Before it happened, Zhang Jun gave her a pill. Zihan complained that there was nothing wrong with her, so why should she take medicine? He said it was a vitamin. He had to coax her for ages before she took it.”

My heart tightened. I turned to my mentor.

He frowned and nodded.

I went to ask Zhang Jun about the pill.

He took a blister pack of softgel vitamin A and D capsules out of his bag and handed it to me.

“These.”

I thought that if Li Zihan really had died after taking a poisoned capsule, it certainly would not be one from the pack he was showing us.

Still, on the off chance, I took it to the laboratory.

Two hours later, a colleague brought the report.

They were ordinary vitamin A and D capsules.

There was no poison in them.