Chapter 289

Wang Bo's sprinting under the sunlight had drawn Yu Wenshu's attention.

The rapid sound of running immediately made Comrade Yu Wenshu realize that the on-site investigation had yielded results.

Yu Wenshu had originally been organizing personnel below, trying to trace clues through the accountant's personal connections—perhaps the victim had beaten someone else's child, knocked down an elderly neighbor, or stolen their takeout, provoking the killer's rage, in which case the case would be solved outright.

Still, Yu Wenshu leaned more toward robbery-murder, so upon sensing Jiang Yuan's breakthrough, he immediately dropped everything else and returned to the scene.

He Guohua was holding the on-site inspection lamp, switching wavelengths, searching for the window frame.

Yu Wenshu glanced and understood at once, his voice tinged with excitement: "Can we find the killer's fingerprints?"

"Maybe," Jiang Yuan replied offhandedly.

Yu Wenshu's eyes widened instantly: "Wait, we can? Can we confirm it?"

"Possibly. We don't know yet—Xiao Bo went to fetch something." Jiang Yuan had no better answer, so he said that.

Yu Wenshu hummed twice, quickly suppressing his rising excitement.

As the captain of the Criminal Investigation Brigade, he was a master at controlling his emotions, but this case was truly wearing him down.

Though the crime had occurred just today, Yu Wenshu hadn't rested a moment since, nor had the entire criminal investigation team. Robbery-murder cases, when they hit a wall, become genuinely difficult.

Watching the case slowly slip away, Yu Wenshu's anxiety multiplied with every passing hour.

Mostly because it was year-end—after everyone had worked so hard all year, if this current homicide case erased all their efforts, Yu Wenshu, as the leader, felt a deep sense of guilt.

And yet this case was slippery as an eel.

From Yu Wenshu's experience, this case matched the modus operandi of a habitual itinerant offender.

Construction sites are inherently chaotic places; in today's labor market, migrant workers demand daily wages and rarely require ID verification. In such an environment, fugitives inevitably slip in.

Even without the fugitive himself working on-site, just chatting with coworkers could reveal where hiring was happening or where payments were due—whether in a temporary dormitory where roommates didn't know each other, or at a roadside meal with strangers. In other words, this lead might be impossible to follow. If tracing the killer's information sources led nowhere, Yu Wenshu's second plan was to pursue the killer's pattern. He had already begun assigning that task below.

With his physical strength and familiarity with construction sites, robbing cash from the site fit the profile of a fugitive's modus operandi perfectly.

If it was a pattern, it might have been used multiple times—except previously, the killer may not have killed anyone, or even caused serious injury, so each incident was treated as isolated.

But Yu Wenshu knew well that even if his hypothesis proved correct, the subsequent investigation would still be arduous.

A fugitive is a fugitive because he has already successfully evaded capture for some time; criminals gradually adapting to fugitive life are hard to identify and arrest.

If Jiang Yuan could find fingerprints, from the perspective of investigative pressure, solving the case would become a manhunt—minimally, it would prevent the loss of 300 points for this current case.

On the other hand, a manhunt under these circumstances is simpler than solving the case outright. His urgency in bringing Jiang Yuan here stemmed partly from wanting to trap the suspect within Changyang City.

The crime happened today—the killer is unlikely to have disposed of over a hundred thousand yuan in cash by day's end, making it less probable he left the city.

But after today, he might find suitable transportation or a way to cash out.

Yu Wenshu had always expected Jiang Yuan's on-site investigation skills; now he simply stayed put, watching from above, and asked: "What's wrong with this window?"

"The killer jumped out through the window," Jiang Yuan said, observing as he repeated his earlier explanation to Yu Wenshu.

Yu Wenshu was stunned: "So you've already confirmed the killer's footprints?"

"Yes," Jiang Yuan nodded.

"That's good—send me photos of the footprints. I'll have people search below immediately to map the distribution." Yu Wenshu was sharp—he instantly saw how to use the footprints.

This time Jiang Yuan slapped his forehead: "I forgot. Team He, send the footprint photos to Yu Zhi."

Yu Wenshu's strategy was extremely useful.

Currently, there were countless footprints within the construction site—including the killer's; nearly everyone entering or leaving left prints.

The reason they couldn't be used was the sheer volume, and more importantly, no one knew what the killer's prints looked like.

Now that they did, Changyang's forensic and on-site investigators could identify every matching footprint on-site and trace where the killer entered and exited.

Although the construction site was less valuable than an indoor scene, determining the killer's route could still push the case forward significantly.

If the killer visited the workers' card-playing room, internal involvement becomes plausible. If his route was singular, perhaps he had scouted ahead…

He Guohua swiftly sent the footprint photos to Yu Wenshu. Yu Wenshu immediately began operating and asked: "What can the footprints reveal?"

"The killer is around thirty, lightweight—likely under 130 jin, about 165 cm tall, male…"

Jiang Yuan had already examined the footprints closely and now delivered the conclusion directly.

Yu Wenshu repeated Jiang Yuan's assessment to his subordinates. Around the same time, Wang Bo ran back.

"I took apart a printer cartridge," Wang Bo said, handing Jiang Yuan a small bottle filled with printer toner. "Now what?"

"Mix the toner with magnetic powder, then try brushing it on. Use a feather brush if possible," Jiang Yuan gave detailed instructions. "When the killer jumped out the window, he likely braced himself with his hands—brief, forceful contact. That fingerprint might have been missed. Even if you want to develop it, it's not easy."

As Jiang Yuan spoke, He Guohua kept nodding. There were too many fingerprints here—no one could collect them all.

Only by identifying the fingerprint's uniqueness could clues be linked. What they were doing now was where the real value lay. Ordinary fingerprints showed up instantly with magnetic powder—those were useless.

Jiang Yuan and He Guohua were like two seasoned players: they ignored easily visible fingerprints, snapped photos, and moved on.

Only when Jiang Yuan, using magnetic powder and printer toner with the feather brush's tip, gently brushed the windowsill repeatedly, did the fingerprint finally reveal itself—slowly, reluctantly—and then both men gave it special attention. "I'll compare it first," Jiang Yuan said, taking the print and immediately beginning to mark its features.

Only after Jiang Yuan used magnetic powder and printer toner, gently dusting with the tip of a feather brush and repeatedly brushing the windowsill to reveal the faint fingerprints, did the two give them special attention. "I'll compare them first," Jiang Yuan said, taking the fingerprints and immediately beginning to identify the minutiae.

Yu Wenshu's heart raced, but he dared not disturb Jiang Yuan. He couldn't help thinking: if this were purely a robbery-murder case, the sentence would be harsher than a typical homicide—most likely immediate execution.

In other words, if this case was solved and the killer caught, his life would begin counting down.

Ningtai Jiang Yuan, his fury raging.

As expected.

As expected.