Chapter 183: This Trick Works

Jiang Fuzhen was scrolling through his phone while sipping duck-shit aroma Phoenix Dancong tea when he received Jiang Yuan's message.

Jiang Fuzhen replied with a simple "Good," then fell into thought.

"Thinking about what?" Uncle Three sat across from him, sipped tea, teased the Huabo Xuetu dog under his feet, and nudged Jiang Fuzhen's two dogs farther away.

The Doberman was only a few months old, but already larger than his Huabo Xuetu; together, the two dogs gave off a vibe like they were daring to tease their uncle.

Jiang Fuzhen grunted, put down his phone, and began brewing tea. "Xiao Yuan's got to work overtime again."

"Working overtime again? Even civil servants are this busy now?" Uncle Three slurped his tea.

"He said there's a case," Jiang Fuzhen said, shaking his head helplessly.

"Looks like second-class merit isn't easy to earn. Others clock in eight hours a day; some go home after four or five. Jiang Yuan works ten hours—second-class merit's practically his by default."

Aunt Hua agreed: "Xiao Yuan really works too hard. He'd be better off coming back to start a business—like a company helping people find things…"

"You mean helping yourself find things," Uncle Three couldn't help saying. "You bought that safe to lock things away, yet you leave it open every day—what's the point?"

Aunt Hua complained: "Opening the safe is exhausting! That door's so heavy—pushing it's fine, but pulling it? I have to drag my legs along the floor, then input the password, scan my iris, place my eye right on it… and it still often doesn't recognize me. I might as well have bought a filing cabinet."

"Aunt Hua, you've got abalone, right? I remember." Jiang Fuzhen asked.

"Yes, I bought a lot of dried abalone back then. Simmering them is too much trouble, and no one in my family really eats them…"

"Give me some. I'll simmer some for Xiao Yuan to nourish him," Jiang Fuzhen said decisively, standing up.

Aunt Hua stood too: "Exactly! Xiao Yuan still doesn't have a partner—he's working this hard, he absolutely needs proper nourishment. I've got dried scallops and Jinhua ham too. Wait a sec, I'll have someone push them over."

"Send me a number via WeChat later," Jiang Fuzhen held up his phone.

"Alright," Aunt Hua didn't refuse. "How much are you cooking?"

"A whole pot—about four or five catties," Jiang Fuzhen said, then started sending messages to order old hens, pork bones, chicken feet, and pig trotters.

Dried abalone is complicated to prepare: soaking requires care, simmering demands time, fuel, and ingredients—roughly ten pounds of other materials for every pound of abalone. The whole process takes days.

But Jiang Fuzhen figured Jiang Yuan wouldn't be home for several days anyway—perfect timing for the simmered abalone.

…

Criminal Investigation Team.

Jiang Yuan rubbed his lower back, stared at the screen, waiting for inspiration to strike before annotating or operating.

Most of the time, Jiang Yuan just stared at fingerprint images, thinking.

Fingerprints are small, but the details demanding attention are countless. Especially with high-degradation, slightly blurred prints—you must synthesize ridge flow, ridge width, feature point locations, and feature point count.

The emergence of automated fingerprint matching systems greatly reduced fingerprint comparison workload.

But conversing with those systems became a complex task in itself.

Sometimes, even after refining the fingerprint to its purest, most authentic form, you still can't find a match.

Because the fingerprints in the database aren't necessarily the purest or most authentic.

Sometimes, to get a match, you need impurities instead.

So, conversing with the program is like conversing with a person.

Initial exchanges and clashes revolve around one question: Are you pure or trash?

Once you determine the nature of the other side, deeper interaction requires treating purity with purity, and trash with trash.

After an afternoon and half-night of trial, Jiang Yuan finally made his judgment:

You're trash.

He said it aloud, facing the computer screen.

The blood fingerprint on screen remained coldly silent, like an elite.

"We'll talk tomorrow," Jiang Yuan tapped the blood fingerprint with his finger, then left the office and headed straight to the dorm to rest.

It was too late—he was afraid to walk home alone.

He'd seen too many cases lately. What if he ran into a released killer, a retired killer, a killer covering up a murder? That'd be disastrous.

Especially on the eve of cracking a long-unsolved homicide case, walking home alone at night—this is practically a death sentence in films. Even if he survived, he'd likely be injured and comatose for weeks, or worse, crippled and forced to smile through a ruined life.

Jiang Yuan returned to the dorm, locked the door from inside, and finally slept soundly.

The next day.

The sun shone brightly.

Jiang Yuan slept until everyone had gone to work, then got up, washed up, and joined them back in the office.

Wu Jun arrived right after him, clapped him on the shoulder, and grinned: "My hand was blessed before I left—giving you some good luck."

"Thank you, Master," Jiang Yuan replied.

"How's it going? Any hope?" Wu Jun, an expert himself, had seen too many fingerprint analysts fail after years of effort. He didn't want to add pressure to Jiang Yuan.

Jiang Yuan nodded. "It's going smoothly."

He felt confident—if today's rhythm held, he could nail this fingerprint. That confidence came from multiple successful matches during the provincial fingerprint campaign.

Still, even with confidence, it was wiser not to boast openly.

Jiang Yuan returned to his seat and quietly adjusted the fingerprint.

The old high-performance host hummed to life again.

This time, he treated the fingerprint as impurity.

After a series of operations, when Jiang Yuan submitted the query again, he selected only the flat fingerprint database and deselected "rolling and flat," "rolling, flat, and palm print," and other databases.

"Rolling" refers to rolling fingerprint capture, also known as three-surface fingerprint capture.

It is a more advanced fingerprint capture method, quite complex to perform.

The subject stands before the fingerprinting desk; the fingerprinting operator stands to his left, pinching the second phalanx of the finger with the thumb and index finger, using the other fingers and palm to control the entire hand, then rolling it outward from the thumb area, centered on the operator…

In short, rolling fingerprint capture is performed by specialized fingerprinting operators—usually police officers.

The advantage is capturing every detail: internal ridge patterns, outer ridge systems, delta systems, triangles…

Theoretically, any partial fingerprint left by this person in the future can be matched against the three-surface fingerprint capture.

Thus, rolling fingerprint capture greatly enriches the fingerprint database—unless…

Unless the fingerprinting operator is unprofessional.

Everyone knows: people do unprofessional things.

And rolling fingerprint capture is still somewhat difficult.

Though with proper training and practicing on dozens of fingers, one can master it.

But everyone knows: people don't take things seriously.

Jiang Yuan faced too few fingerprints—zero tolerance for error.

In contrast, flat fingerprint capture was simple.

It's what ordinary people understand as pressing a fingerprint.

A finger dipped in ink is pressed vertically onto the card. Although the recorded print is incomplete, the fingerprint Jiang Yuan now held fell entirely within the range of flat fingerprint capture.

Impurity matching impurity—no need to feel ashamed.

Jiang Yuan readjusted the fingerprint's feature points, selected only the flat fingerprint database, and ran the comparison.

After two rounds, at noon, as Jiang Yuan redrew the third set of feature points, the fingerprint ranked #12 made him pause.

Jiang Yuan sipped tea, then zoomed in on both prints, comparing them point by point.

Match confirmed!

Indeed, when selecting only the flat fingerprint database, matching became suddenly easy.

Jiang Yuan exhaled softly.

In terms of difficulty, this fingerprint was even harder than those during the fingerprint campaign.

During the campaign, he'd used image-enhancing skills—essentially a dimensional advantage over older forensic technicians.

This time, the fingerprint match was pure, direct confrontation.

But how could a cold case ever be easy?

Jiang Yuan submitted the match in the database. Soon, feedback returned.

Same identification!

Jiang Yuan stood, stretched, bones cracking loudly. He picked up his phone and said to Wu Jun: "Matched."

"Huh? Really?" Wu Jun was startled.

Jiang Yuan nodded. "I'll call Chief Huang."

"Old Huang'll be overjoyed," Wu Jun said, then stared at his right hand, deep in thought: Is this trick really that effective?