Chapter 24

Afternoon, after tidying up a bit, Jiang Yuan and Wang Zhong each rode their own electric scooters to the crime scene residential complex.

The red-brick apartment building, located in the suburbs, still bore a distinct era’s character; the two-way, four-lane side road was lined with trees of questionable species on both sides and in the median, while sparse shrubs revealed the area’s mediocre maintenance level—but the trees, grown over time, still preserved the basic quality of the residential zone.

This was the distant outskirts of the county, yet due to nearby factories, it was more prosperous than many areas within the county itself.

Of course, prosperity, not affluence. Looking around, patch after patch of old residential complexes and new temporary structures kept the environment firmly at the level of an aging industrial zone.

Small convenience stores were the dominant commercial model here, and shop fronts were mostly outdated, unlikely to spark any desire to spend.

And these shops, too lazy to even hang a curtain, had no interest in installing surveillance cameras either.

Municipal development here seemed to have stalled alongside time. The old road infrastructure was still well-maintained, but only to the standard of its original era; newer, better improvements had almost entirely failed to appear.

The crime scene complex appeared more desolate than other complexes along the same road. Only the main gate had a few elderly men gathered, watching everything around them with suspicious eyes. The complex’s other two entrances had been chained shut. These measures, originally intended for public convenience, were now seen as the root cause.

“What are you here for?” An old man bravely blocked their path as Jiang Yuan and Wang Zhong rode their scooters toward the entrance.

“Police.” Both had come in plain clothes, so they pulled out their police IDs and showed them.

The old man frowned: “I heard there are people now making fake police IDs to scam folks—are you one of those fraudsters…?”

“If you don’t believe us, call 110,” Wang Zhong said, then added: “We’re here for a re-inspection. Would you be willing to serve as witnesses?”

The old man had already pulled out his phone to dial 110, but froze at the words: “What?”

“We’re going inside to check the scene, look for any remaining evidence. You just stand inside and watch. Later, you just sign your name,” Wang Zhong explained succinctly.

China’s criminal case scene investigation witness system requires investigative agencies to invite third-party civilians to witness the examination and inspection of crime scenes. This is fundamentally different from the American judicial system often portrayed in films and TV dramas.

The U.S. uses a self-certification method, mandating audio recording of scenes to ensure police self-verify the fairness and standardization of their investigations. By contrast, Japan and Russia also use witness systems, though each differs in detail.

Simply put, countries with witness systems require an outsider to observe every piece of evidence collection, aiming to minimize false testimony. In countries like the U.S., which lack such systems, each officer must self-regulate; if false testimony emerges, all cases handled by that officer may be questioned.

Though practice often falls short, as junior officers, Wang Zhong and Jiang Yuan followed protocol strictly.

In fact, randomly picking one or two passersby still didn’t fully align with the spirit of the witness system. Fundamentally, this system calls for individuals who understand the scene, have some grasp of criminal investigation, and are unconnected to the case—ideally, those who could witness multiple inspections throughout the process.

But under current conditions—where the public lacks awareness, witnesses receive no compensation, police are overwhelmed, and judicial standards are low—such requirements are clearly impractical. Police prefer witnesses who are obedient, cooperative, non-disruptive, and unlikely to leak information.

Two elderly men, not yet retirement age but retired early due to corporate decline, were perfect. Far more compliant than using auxiliary police as witnesses.

The old men at the gate, perhaps bored and idle, or perhaps intrigued by the murder in the complex, asked many questions before reluctantly watching the two young old men enter the building where the crime occurred.

Wang Zhong fetched the keys from the office, casually lifted the crime scene tape, opened the door, entered, locked it, and changed into his gear. He ordered the two elderly men, who were technically retired but not yet of retirement age, to stand in the corner—no talking, no moving, no taking photos.

“Where do we start?” Wang Zhong hadn’t planned to come—he had little confidence in re-inspecting—but Jiang Yuan had ideas, so he followed.

Jiang Yuan looked around slowly and said: “Let’s start from the beginning.”

As he spoke, a semi-transparent interface slowly unfolded before him:

Task: Start from the Beginning

Task Description: Re-inspect the Xue Ming crime scene to obtain clues and evidence.

Jiang Yuan stared at the system interface for several seconds until it vanished.

“Start from the beginning?” Wang Zhong looked confused, then leaned close to Jiang Yuan and whispered: “Is it necessary?”

“Give it a try,” Jiang Yuan said, setting up his equipment, then picking up a glass from the shoe cabinet near the entrance, dipping a cotton swab in water, and gently wiping it.

Though he had known Jiang Yuan longer and had more seniority, Wang Zhong deeply trusted him. Skills like fingerprint analysis revealed skill gaps too clearly to ignore.

After standing still for a moment, Jiang Yuan’s actions left Wang Zhong speechless.

Ordinary scene investigators—or those in Ningtai County—would wipe a glass by simply running a cotton swab once around the rim. This method could collect possible DNA, but it was always a crude, often inadequate technique.

Jiang Yuan’s method, however, was one Wang Zhong had seen only rarely. Jiang Yuan first moistened the cotton swab, then pinched it gently until it was damp but not dripping. He didn’t wipe broadly—he chose one spot on the rim, rubbed the swab up and down with even pressure three to four times, aiming to extract any possible DNA.

After finishing one spot, he moved to another point, repeating the process multiple times before completing the DNA extraction from a single glass.

This method naturally took far longer than wiping the entire rim, but the probability of successfully extracting DNA was much higher.

Though Wang Zhong had never tried Jiang Yuan’s method before, from the details Jiang Yuan displayed, Wang Zhong knew his level was genuinely superior to the rest of the team’s scene investigators.

For example, a slightly damp cotton swab transferred DNA more effectively than a dry one or one soaked in water—the principle being: don’t make mud, don’t soak it.

Using a northern Chinese analogy: the cotton swab is like a washcloth. Rubbing a dry washcloth on dry skin removes little. A washcloth soaked in water just slips uselessly. Only a slightly damp washcloth on slightly damp skin works best, removing the most grime.

Using a non-northern analogy: the cotton swab is like a tongue. A dry tongue licking dry skin removes little. A tongue soaked in water also performs poorly. Only a slightly damp tongue on slightly damp skin achieves optimal friction and effectiveness.

Similarly, Jiang Yuan’s method of targeting specific points was far more effective than wiping the entire rim; again, using the northern analogy: targeted rubbing versus sawing back and forth—what’s removed cannot be compared; using the non-northern analogy: licking one spot is more effective than licking everywhere randomly.

Jiang Yuan clearly had real skill. Wang Zhong stopped questioning and simply followed him, assisting as needed.

After years working in the forensic unit’s trace evidence post, Wang Zhong long understood: seeing something and thinking you understand it—even thinking it’s simple—doesn’t mean you can conceive it. Even if you conceive it, you might not apply it correctly. Even if you apply it correctly, you might not apply it well. Even if you apply it well, you might not apply it quickly.

Using an example any graduate of nine-year compulsory education would understand: Euclidean geometry has only five formulas; Newton’s three laws total barely a hundred characters. Anyone can understand them after a lesson. But seeing a problem, you might not know which formula to use. Even if you know, you might use it wrong. Even if you use it right, you might not use it well. Even if you use it well, you might not use it fast.

Wang Zhong had spent years on scene investigations. Seeing Jiang Yuan work with such meticulousness, speed, and precision, he was simply awestruck. Fortunately, during fingerprint work, he’d already grown accustomed to assisting Jiang Yuan—first time awkward, second time familiar, gradually smooth, even pleasant.