A real killer playing a villain; the guy surnamed Zhen in Detective, run!

"Collect. Return everything to the station." Jiang Yan's voice boomed from deep within the power distribution room. "Take samples from all contact surfaces: the inner walls of the underground drains, the seams of the cover plates, and the bottom of the moisture-proof membrane. The trace evidence team will stay on-site until dawn; not a single speck of dust will be missed."

The taillights of the police car pierced the deathly silence of the southern suburbs.

In the conference room on the fourth floor, the lights started humming again.

Old Qi wrote the five conditions at the top of the whiteboard:

First, have worked or lived in the southern suburbs for more than two years.

Second, possess surgical skills at the level of a surgical resident or above.

Third, there is a way to access the Stryker System 7 oscillating saw.

Fourth, it can produce large quantities of hydrogen peroxide and sodium hypochlorite.

Fifth, severe obsessive-compulsive disorder and morbid cleanliness tendencies.

Five anchor points were superimposed into the big data cross-comparison system, and the screening scope was narrowed down to 72 square kilometers in the southern suburbs.

Old Chen from the IT team stared at the screen for four hours straight. At eight o'clock in the morning, the initial screening results came out. Thirteen doctors.

All of them are registered surgeons from tertiary and secondary hospitals in the southern suburbs, ranging in age from 31 to 57, with the shortest years of practice exceeding six years.

Everyone rushed forward.

In 48 hours, 300 people were investigated, and 13 files were thoroughly examined.

The result was like being doused with ice water from head to toe.

These thirteen people were so clean it was despairing. They had normal social relationships, stable family structures, no history of violence, no mental health records, and were universally praised as good people by their neighbors and colleagues.

The trajectory comparison by Skynet was even more breathtaking: no one deviated from their normal life route within the time window of the crime, not even a record of returning home half an hour late.

Morale plummeted to rock bottom.

Jiang Yan stood in front of the whiteboard, staring at the thirteen printed ID photos.

That's perfectly normal.

Her gaze shifted from the photograph to the map with a hole punched in it on the right side of the whiteboard. A voice inside her head rang.

"The timing of streetlights being switched on and off, the frequency of garbage trucks passing by, and the shift changes at convenience stores have all become part of my body's rhythm."

"He doesn't need to calculate at all."

Jiang Yan's back left the wall.

No calculation is needed.

It's because it's too regular.

She turned to face the long table, and a dozen pairs of bloodshot eyes stared at her.

"The direction is wrong."

Old Qi's reading glasses slid down half an inch from the bridge of his nose.

"We've been looking for anomalies: unusual travel, unusual purchases, unusual social relationships." Jiang Yan walked to the whiteboard and bit off the pen cap with her teeth.

"But this killer doesn't exhibit any abnormalities. He's the opposite. His pathology manifests itself precisely as an unbiased, second-precise, machine-like regularity."

The pen tip drew a horizontal line on the whiteboard.

"Don't look for the most suspicious. Look for the most perfect."

The meeting room was silent for five seconds.

Old Chen was the first to react, turning around and rushing back to the keyboard.

The filtering criteria have been reversed: instead of searching for data anomalies that deviate from the norm, the criteria are now used to search for behavioral patterns with the highest repetition accuracy.

Access control. Time clock. Vehicle entry and exit. Supermarket purchases. Dry cleaning pickup and delivery. Pharmacy purchase records. Registration frequency.

Four hours later, Old Chen's voice drifted out from behind the screen, sounding somewhat unsteady.

"Captain Jiang, come and take a look at this."

On the screen, a timeline was marked in blue.

Lin Qinghui, Deputy Chief Physician of Surgery at the Third Municipal Hospital. Male, 41 years old, PhD, a key member of a top-tier hospital.

His clock-in time is 7:47 AM. For 430 consecutive days, the error has been within plus or minus 15 seconds.

I left work at 5:21 PM. Same level of precision.

The time difference between a vehicle entering and exiting the community's access control system, from startup to the lifting of the recognition barrier, is consistently between eleven and thirteen seconds.

I go to the same dry cleaner every Tuesday and Friday. I always arrive at 6:06 PM.

Old Chen scrolled down, and the screen was filled with densely packed data. Each row of numbers was so neatly arranged it looked as if it had been measured with a ruler.

"His life trajectory is not like that of a person, but like the movement of a clock."

Old Qi leaned closer and pushed his reading glasses up to his forehead.

"A regular work-rest schedule alone is not enough to convict someone."

Old Chen clicked on the next page.

"He applied for sodium hypochlorite compound solution six times in the hospital's procurement system under the name of the department. The quantity far exceeded the department's normal consumption. Four boxes of the brand of sterile disinfectant gel involved in the case were also applied for in the same batch."

"Property information: In addition to my current residence, I also own a high-end apartment in the cotton mill area of ​​the southern suburbs. It was purchased two years ago, property management fees are paid regularly, and water and electricity usage is extremely low. It is located near the abandoned power distribution room—"

Old Chen measured something on the map with his finger.

"Seven hundred and sixty meters."

Old Qi took off his reading glasses, held them in his hand, and bent the temples of the glasses.

By day, a gentle and refined deputy director of surgery, known among his colleagues as a scalpel expert at the operating table. By night...

That scene doesn't need to be imagined.

---

It was 11:40 p.m. that night.

Three SWAT assault vehicles and two plainclothes cars completed their encirclement of the target apartment building. All police lights were off, radios went silent, and everyone held their breath.

Jiang Yan, wearing a bulletproof vest, stood behind the load-bearing pillar on the side of the unit door.

Seventeenth floor. The elevator has been locked by the property management. Two teams of assault personnel are ascending the fire escape stairs.

Her hand rested on the walkie-talkie on the side of her tactical vest, listening to the floor report coming through her earpiece.

"The fifteenth floor has been approved."

"Passed on the sixteenth floor."

"Seventeenth floor, ready outside the target room."

"Open the door."

The sound of the hydraulic door breaker biting into the lock cylinder and the sound of the door panel coming off the frame came almost simultaneously.

Jiang Yan followed the second group and rushed in.

The marble floor tiles in the corridor were so shiny they reflected your image. There was a faint scent of citrus essential oil in the air.

The living room lights are on.

A man wearing dark blue silk pajamas stood with his back to the door, a sterile medical glove on his right hand, holding an alcohol wipe in his other hand, wiping the edge of a marble coffee table.

The wiping motion was even and repetitive, with the wet wipes folding back and forth along the same path without deviation.

Six guns were pointed at him.

Lin Qinghui walked the wet wipe around the edge of the coffee table again, folded it, put it into the transparent plastic bag next to him and sealed it, and then slowly stood up.

His gaze swept from left to right, finally settling on the feet of the SWAT officer who had stepped into the lobby.

"Your military boots stepped on my wool carpet." He frowned slightly, his tone one of disgust. "I counted, one hundred and twenty-seven mud stains. So filthy."

The expression behind the SWAT team leader's mask froze for a moment.

Jiang Yan stepped out from behind him, holding the search warrant at chest height.

"Lin Qinghui, Deputy Chief Physician of Surgery at the Third Municipal Hospital. Search warrant issued by the Municipal Intermediate People's Court."

Lin Qinghui's gaze swept past the search warrant and returned to Jiang Yan's face.

"Captain Jiang, I've heard so much about you."

During the process of being pinned down on the sofa by two special police officers, his only movement was to straighten his crooked sleeve.

"Please note, this is Italian silk. Don't stretch it out of shape, it can't be washed back to its original state."