Officer Sun told me that this case dated back ten years. At the time, he was just a junior squad leader in the criminal division. Everything he had accomplished since then was thanks to my grandfather.
My grandfather was an eccentric man who rarely stepped in on cases. But whenever he did, he always found the truth.
It happened on a moonless night. He was delivering documents to a local precinct when a middle-aged man stumbled in, holding a plastic bag. His face was flushed as if he were drunk, and he shouted that someone wanted to kill him—before collapsing to the floor.
At first, Officer Sun thought he was just a drunk, but upon checking, the man was already dead.
Inside the plastic bag? A human heart.
There were no injuries on the man's body. He looked like he was simply asleep. No signs of struggle. No poisoning. His car was still running outside, and it bore only his fingerprints. He had driven himself to the station... and died there.
When the police checked his identity, they discovered he was a judge.
The authorities took the case extremely seriously. The best forensic scientists and detectives were brought in. A special task force was formed. But after days of investigation, they had no leads—not even a cause of death.
The task force was made up of elite talents, yet their cooperation was a disaster. Arguments broke out constantly, and everyone worked on their own theories.
As the lowest-ranking member, Officer Sun had no real voice. When he suggested bringing in my grandfather, everyone laughed. "Why not just get a Taoist priest?" they mocked.
Then the second murder happened.
The victim was a wealthy female entrepreneur who had recently returned from overseas. Just like the first case, a plastic bag containing a human heart was found beside her body.
Still, there was no progress in the investigation.
Desperate, Officer Sun brought the case files to my grandfather. He agreed to help—but when they arrived at the crime unit, both bodies had already been autopsied.
The medical examiners had torn them apart, and all they discovered was that the hearts in the bags belonged to the victims. Somehow, the killer had extracted them without leaving a single mark on their bodies.
My grandfather was furious. His only condition for assisting the police was that no one touch the corpses before he examined them. Sun begged him to stay. Finally, my grandfather agreed—but asked to visit the victim's home.
The house had already been combed through. All they found were police footprints and fingerprints. The killer had left nothing behind. It was as if he didn't exist.
But my grandfather wasn't like other investigators. He pulled the curtains shut, lit a bundle of mugwort, and let the smoke fill the room.
Then, on the walls, eight bloody characters appeared:
"North River Blade—Punisher of the Corrupt."
It was a calling card. "North River Blade" was likely the killer's alias. The message declared himself judge and executioner of the wicked.
Officer Sun ran back to dig up the victims' histories. The judge had once taken bribes that sent two innocent men to prison. The female tycoon had invested in cancer drugs, inflating the price from pennies to thousands of yuan.
To the killer, they were guilty—and he had passed judgment.
Soon, a third victim turned up. A university professor. He had manipulated his female graduate students, filmed them, and blackmailed them with the footage.
He was killed at an academic seminar, in full view of reporters. There was no hiding it this time.
As media coverage exploded, some people celebrated the killer online, calling him a hero who rid society of evil. Public pressure on the task force skyrocketed.
But no matter how flawed the justice system may be, no one has the right to take the law into their own hands. Murder is murder.
This time, my grandfather was granted full access to the body. He locked himself in the morgue for a whole day and night. Officer Sun stood guard the entire time.
When Sun briefly stepped away, a trainee pathologist accidentally opened the door. What he saw terrified him—my grandfather and the corpse both wore strange masks. The body was strung up by two ropes, as if my grandfather were reenacting the murder.
The next day, my grandfather burst into laughter.
When asked if he had found anything, he said:
"This case has stumped me. I still can't figure out how the killer removed the heart without a trace."
But he wasn't entirely empty-handed.
"The corpse told me this—male, 180 cm tall, thin build, triangular eyes, sharp brows, high nose bridge."
That was his exact quote.
Officer Sun, knowing how reliable my grandfather was, mobilized the force to search the entire city for suspects fitting the profile.
They didn't find the killer—but they found a key witness: a former gang member named Zhang Bao.
Bao had served only three years for manslaughter and recently saw a suspicious man lurking near his home who matched the description. Fearing he'd be the next victim, he begged for protective custody.
My grandfather read his statement and cross-referenced it with the three murders.
Then he pulled out a city map and began drawing strange symbols on it.
"Search these marked streets," he ordered Officer Sun.
When asked how he knew, my grandfather offered no explanation—just told him to hurry.
The police conducted door-to-door inquiries in those areas. Eventually, a landlord said a man matching the description had recently rented a unit from him—and even left a rental contract with his information.
Overjoyed, Officer Sun sent two officers to collect the documents. Meanwhile, others raided the residence.
Inside, they found newspaper clippings, photos of the three victims—and Zhang Bao's picture, all stabbed into the wall with a dagger.
It was clear.
They had found the lair of the infamous North River Blade.