Chapter 290: Short Hair, Scar

Everyone had something to do, except Wang Bo, who had neither work nor an assignment, so he quietly pulled out his phone, took a few photos, and sent them to the work group.

The forensic technicians and crime scene investigators in the work group had been dying of curiosity.

When they saw this new message—another fingerprint discovered—they instantly went into shock mode.

A fingerprint meant the possibility of directly identifying the killer; failing to find such critical evidence—or finding it now—was utterly astonishing.

Li Yuanliang: "Did Jiang Yuan find this fingerprint? Where is it? Is it somewhere our scanners missed? @Wang Bo"

Wang Bo sent another photo of the fingerprint's location: the bottom edge of the window frame, a relatively obvious spot. Li Yuanliang: "This wasn't scanned? Are you kidding?"

Wang Bo: "It was a quick-pressure fingerprint, extremely faint. Jiang Yuan used laser printer toner mixed with magnetic powder and brushed it several times before it showed up. When I first saw it, I thought it was amazing—it's different from regular powdering."

Wang Shouming: "Can powdering even produce flowers?"

Wang Bo: "The first time, nothing showed. The second time, faint traces appeared—only visible under the forensic lamp. After brushing two or three more times, it gradually became clear. I've never seen powdering like this before."

Normal fingerprint powdering: sprinkle the powder, the print appears. Sometimes it's unclear—just not enough adhesion—so you add more powder, and it's fine.

But this fingerprint, using printer toner mixed with magnetic powder, required brushing three, four, even five times—gradually becoming clearer. Wang Bo had never seen or learned this method.

The Changyang City work group fell silent.

After a long while, someone spoke again: Li Yuanliang: "I asked an expert. He said laser printer toner has a density close to copper and aluminum powder, with a specific gravity between aluminum, copper, and magnetic powder, and slightly weaker magnetism than magnetic powder—mainly static electricity. It can be used alone or mixed with magnetic powder in varying ratios depending on season and environment, compensating for the loss of fine particles during prolonged powdering… What the hell? You have to adjust powdering based on season and environment?" Wang Shouming: "Fake, right? If it's this useful, why don't we just equip every crime kit with it?" Li Yuanliang: "I'm just quoting the expert—don't blame me. His exact words: 'If you're not an expert, using printer toner will only make things worse. If you can use it skillfully, just kneel down and call him Your Majesty.'"

Wang Shouming: "Who talks like that?"

Li Yuanliang: "My uncle said it."

Wang Shouming: "... If my uncle says it's true, then Your Majesty, Your Majesty, ten thousand years!"

Wang Bo's forehead was already throbbing from reading.

Although everyone chatting in the group were colleagues—even superiors—Wang Bo still carefully chose his words before replying.

Wang Bo: "When I was in school, professors taught us never to re-brush. One or two applications are fine—if it's not clear, re-brushing easily smears or destroys the ridges, or turns everything black. Only in extremely dry conditions is re-brushing allowed..."

Wang Shouming: "Xiao Bo, I don't understand either, but let me say this: theories? Just listen. Watch the masters work—cheering '666' is safest."

Li Yuanliang: "Don't corrupt the youth. This is debatable—I just looked up some info..."

"Jiang Yuan's method uses a complex ratio mix—don't even try to guess. I think the real question is: why did he re-brush the windowsill? Did he find something? @Wang Bo"

Wang Bo: "He found footprints."

Wang Bo then described everything that happened after Jiang Yuan arrived. The technicians and non-technicians in the group fell silent. Jiang Yuan's footprints didn't need powdering—they were simply there. But everyone had seen too many footprints; no one thought to look down at the window.

The second floor of the steel-framed building was about three meters high, like a normal second floor.

Crime scene investigators wouldn't assume the killer escaped by jumping out the window.

Why? So far, no eyewitnesses. The front door was wide open. The killer walked in normally, killed the cashier normally—why not walk out normally? Li Yuanliang: "Something must have gone wrong. Otherwise, if the killer left through the door, he'd leave no fingerprints and no footprints—at least nothing to distinguish him."

Gao Long: "Killing the cashier was the accident. Normally, no one plans to kill."

Li Yuanliang: "Too much emotional outburst?"

Wang Shouming: "Emotional outbursts are normal. Anyone involved in a robbery gets an adrenaline rush—it's natural. If you're used to it, that's terrifying. There probably aren't any bandits like that anymore."

"Xiao Bo." He Guohua called out, snapping Wang Bo out of his phone trance.

"Ah, let me check what the group's saying." Wang Bo quickly smiled at his master.

He Guohua said seriously: "Take Brother Jiang to the crime scene vehicle and turn on the computer."

"Okay. Use the backend?" Wang Bo asked quickly.

Jiang Yuan said himself: "I want to compare fingerprints on the computer."

He had marked feature points on his phone once but found no match. After re-brushing and re-photographing, he planned to use the computer—screen size matters. Details are too hard to see on a phone.

Wang Bo quickly agreed and led Jiang Yuan down from the steel-framed building.

The two walked slowly along the acrylic bridge. After a while, Wang Bo couldn't help whispering: "Brother Jiang, why did the killer jump from the second floor?"

From Wang Bo's tone, Jiang Yuan heard intense curiosity. He glanced at Wang Bo, then said: "We can ask him when we catch him?"

"That... only by asking?" Wang Bo felt itchy all over, slightly disappointed. A case solved by asking—could that be called solving? Jiang Yuan sensed Wang Bo's discomfort, smiled, and asked: "Must you guess?"

Wang Bo immediately perked up: "What do you think the reason is?"

"Too lazy to guess. Not interested." Jiang Yuan said plainly: "I just like doing technical work. For me, finding footprints is more interesting than matching fingerprints or finding DNA."

Wang Bo: "Ah—really? Even as tech staff, just... just this?"

He said it twice—clearly using polite language to mean: "That's it?"

Jiang Yuan: "The Provincial Department's Liu Jinghui probably fits your taste—he likes deduction."

"He's the kind who just guesses... no, the kind who deduces—I don't like that either." Wang Bo felt embarrassed and added quickly: "I'm not saying his methods are bad, just personal preference."

Jiang Yuan understood. People are diverse. The more cases you handle, the more you realize this. Some crave power, some money, some women, some... well, some like to play with dogs. Others like deduction. Or like Wang Bo—enjoying both tech and deduction...

With a major breakthrough in the case, Wang Bo now saw Jiang Yuan differently.

As they talked, Wang Bo gradually relaxed and blurted: "I think purely technical case-solving has limits."

Jiang Yuan: "Of course."

Wang Bo: "I mean—if you hadn't deduced the killer's route, or if the ground where he landed wasn't soil but clean concrete with no footprints—or if he cleaned them up—would this case just collapse? Thinking about it, it feels impossible."

Jiang Yuan shook his head: "It would get harder, but not impossible."

"There are other ways?"

"Of course. The most direct method: scan the entire room. Collect every footprint, then compare them with the external footprint trail."

"That's a huge workload."

Jiang Yuan glanced at Wang Bo: "So many people are idle—why worry about workload? For homicide cases, as long as you have a plan, manpower is the team leader's problem."

"Ah... this..." Wang Bo had to admit, this method might actually flush out the killer.

Though the construction site had many footprints, only a few entered the cashier's office—maybe ten people. Identify those footprints, map them on paper, trace their paths—some would have low suspicion, others high. That would narrow the suspect pool.

Jiang Yuan continued: "Then, reverse-tracing footprints might reveal a set starting beneath the cashier's window. In that case, the window fingerprint still has a chance of being confirmed."

Wang Bo nodded instinctively. Yes—if done carefully enough, finding footprints beneath the window would raise suspicion.

"If footprints inside the room are properly organized, they might also reveal the killer's route. But this fingerprint? Finding it took real effort." Jiang Yuan summarized. Wang Bo agreed deeply: "Most people probably don't know the toner-and-magnetic-powder method."

"Think positively—if the killer had worn gloves, he wouldn't have left fingerprints either."

"Then what do we do?"

"So mastering more techniques is always better." Jiang Yuan paused, thinking: "If we can confirm the footprints, finding the killer's vehicle might lead to a breakthrough."

Wang Bo froze: "Right! Earlier we couldn't find a vehicle because we had no lead—but now we have footprints. We can trace vehicles. Should we report this to leadership?"

"Call and report." New leads must be followed.

Of course, Jiang Yuan cared more about the fingerprint.

But as he'd said, with so many people involved, following the vehicle trail added more leads and evidence—never a bad thing.

At the construction site entrance, Jiang Yuan got the computer, connected to the internal network, and began fingerprint comparison himself.

Around the same time, more detectives and technicians sprang into action.

Yu Wenshu was indeed interested in the new leads and direction. Fingerprints weren't guaranteed to yield results—he was happy to expand the investigation.

The walkie-talkie left in the crime scene vehicle occasionally crackled. Inside and outside the site, everything was now active.

Inside, technicians were preserving footprints. Outside, detectives were searching for vehicles.

Just beyond the site, the streets grew busier with shops. Police surveillance didn't cover every spot—but someone's home camera might have caught the killer. It just meant knocking on every door.

Jiang Yuan pulled up the fingerprint, carefully marked feature points, and compared them meticulously...

"Hmm, still too small a screen." Not long after, Jiang Yuan matched the fingerprint.

As expected, the suspect, Qi Penghu, was a fugitive with a criminal record for theft and robbery, involved in a black society case. The photo showed Qi Penghu: short hair, short nose, large mouth, rough skin, a scar beside his eye...

His menacing appearance made him look like someone who couldn't even land a normal job.

Jiang Yuan submitted the match in the backend, stretched, and glanced around.

The site was called "Binhu Spring Landscaping Project," located in Changyang City's old district, surrounded by bustling areas. Passersby and local residents paused to stare at the police and patrol cars coming and going. Some bold, bored onlookers stood nearby, watching.

Jiang Yuan turned his head and saw a man with a distinctive face—around thirty, short hair, short nose, large mouth, rough skin, a scar beside his eye...

He looked down at the photo on his notebook, regretting he'd come too hastily—hadn't even brought Mu Zhiyang along.

In a hurry, they didn't even call Mu Zhiyang over together.