National Forensic Doctor-Chapter 1116 - 1047: Winning Amidst Competition

"This area is likely a region Xu Li might have come into contact with. Zone Two." Deputy Captian Qi Yongmiao pointed out the designated area to Jiang Yuan, his tone slightly tense.

Earlier, Jiang Yuan had already extracted a fingerprint from the corpse’s middle finger using the oil lifting technique from Body Number One. Now, if they’re able to find a matching fingerprint from anywhere in the supermarket, it would conclusively prove that Xu Li is the deceased.

A more definitive approach would be to obtain identical DNA. Despite Body Number One being highly decayed, DNA had still been successfully extracted. But since Xu Li was an orphan and the room he rented had been handed over to other tenants, investigators attempted to collect potential DNA samples but found such comparisons to be more challenging.

On the other hand, as a supermarket shelf stocker, Xu Li would have easily left fingerprints behind within the store.

While waiting for Jiang Yuan, Wu Junhao and his team had already narrowed down areas within the store that Xu Li might have interacted with using surveillance footage. However, no matching fingerprints had been found in Zone One.

Qi Yongmiao had held his breath then.

Had it not been Jiang Yuan personally conducting the fingerprint lifting, Qi Yongmiao might have called for someone to redo the process.

Jiang Yuan remained calm as ever. He was taking the matter seriously, so he had come personally to lift the fingerprints. Meanwhile, Liu Jinghui and the others, accompanying him, analyzed the supermarket, considering Xu Li as the victim as they began pondering their next moves.

Zone Two consisted of a shelf at the back of the storage room. Surveillance footage showed that while others had interacted with this spot after Xu Li, the frequency was low, the instances were few, and—more importantly—there was no evidence of wiping, making it conducive to preserving fingerprints.

Jiang Yuan picked up a gray squirrel hair brush, selected silver powder, and meticulously began brushing it onto the dark background of the shelf. A smattering of fingerprints quickly emerged.

Jiang Yuan examined the fingerprints closely and chose only to extract the middle finger prints.

Extracting others would be pointless since only a right middle finger fingerprint had been found on the first corpse.

The recently collected prints from Zone Two had yet to reveal a suitable match. Jiang Yuan surmised that Xu Li may not have left prints of his right middle finger there, or if he did, they may have been accidentally wiped off. Therefore, despite not achieving a match, he wasn’t overly agitated.

Anyone in fingerprint analysis knows that such outcomes are common—the confidently expected fingerprint that fails to match. Every forensic technician has faced this, and a few years into such work often leads to steadier—or more broken—attitudes.

From another perspective, even when a criminal investigator confidently identifies a suspect or victim, it’s possible they may not truly be one. Techniques such as fingerprinting and DNA analysis not only catch many perpetrators but have also exonerated many innocent individuals.

Sometimes, coincidences occur. Situations arise that defy logical reasoning. Such scenarios are uncommon, but when they happen, only the most clear-cut technology can pull the case out of the mire.

Jiang Yuan now aimed to use technology to confirm Xu Li as Victim Number One. While everyone—themselves included—was practically certain that Xu Li was the victim, there remained an undeniable chasm between belief and evidence.

And that chasm ought to exist.

Jiang Yuan carried out on-site fingerprint lifting, comparing each extracted fingerprint as he went.

This type of comparison didn’t involve computer software, leaning instead toward early fingerprint matching techniques—a one-to-one comparison of differences between two fingerprints—as if software had provided shortlisted candidates, and manual confirmation was the final step.

Jiang Yuan didn’t even need to mark minutiae points. He had memorized the prints from the original body long ago. Now, all he needed to do was confirm whether the newly lifted prints aligned.

This sped up the comparison process. After extracting six or seven fingerprints, one fingerprint prompted Jiang Yuan to single it out.

At first glance, this fingerprint appeared slightly different from the original fingerprint on the deceased. But those knowledgeable about fingerprints know that prints left on objects are not always uniform.

The pressure exerted during contact causes fingerprints—the ridges and grooves on fingers—to either spread out under greater pressure or concentrate under lighter pressure. Additionally, a skewed angle during contact can leave partial fingerprints rather than complete impressions.

If a living person were present, they could roll out a complete fingerprint, simplifying comparisons substantially. But with the victim deceased, comparing two partial prints without omissions would likely demand at least Level 2 fingerprint expertise.

Jiang Yuan naturally employed full-spectrum analysis.

Using Level 6 fingerprinting methods under such circumstances was akin to the joy of a lighthouse keeper returning home to his delicate young wife after a year of isolation on the island.

Jiang Yuan spent slightly more time analyzing the fingerprint before him, though only to confirm.

Moments later, Jiang Yuan straightened up, stopped lifting further prints, and nodded, stating, "The match is confirmed. It’s indeed Xu Li’s fingerprint."

Every officer present grew excited.

Not only did this resolve the question of Victim Number One’s identity, but it also represented a major breakthrough in the case.

Immediately, Liu Jinghui said, "I’ll contact Technical Investigation to see if we can trace anything from Xu Li’s phone number."

If the perpetrator used Xu Li’s phone to send messages after his death, it indicated the criminal exposed themselves during that moment.

Many of the techniques employed by Technical Investigation are incredibly difficult to evade in day-to-day scenarios.

Even if the perpetrator knows how to avoid detection, they would need to make certain concessions—or compromises—to do so. Such changes in behavior might lead to crucial clues.

Liu Jinghui didn’t concern himself with probabilities. He figured it best to begin investigations anyway.

Jiang Yuan naturally approved.

The perpetrator using the deceased Xu Li’s phone to send messages was a major lead in itself.

Liu Jinghui then directed his team to collect surveillance footage from surrounding shops and the property management office. Pulling Jiang Yuan aside, he spoke quietly, "The perpetrator schemed carefully; this murder was certainly meticulously planned. Xu Li disappeared the day after receiving his paycheck. It’s difficult to argue this is an isolated event. However, this also exposed the perpetrator."

"What are you suggesting?"

"The perpetrator is likely someone familiar with Xu Li—or at least someone who has access to information about him. Therefore, murdering Xu Li was not a random act." Liu Jinghui exhaled slowly, his eyes lighting up. "They believe such familiarity lowers their chances of being discovered, but it also deepened their connection to the victim."

"Xu Li is an orphan," Jiang Yuan said, reiterating known details, before adding thoughtfully, "He was a supermarket stocker. His daily interpersonal network should not be extensive."

"From the perpetrator’s perspective, this aspect of Xu Li might have been necessary," Liu Jinghui’s train of thought became increasingly clear. "The perpetrator seems to have slain three victims in succession, but their plan may have been in progress for a long time. To kill serially, their aim is often for the first or second victim to remain undiscovered for as long as possible. Based on their planning, if the victim had family, the odds of detection vastly increase when the family files a missing person report. Xu Li appearing in the missing persons database would have heightened our chances of locating him."

Jiang Yuan nodded noncommittally.

Continuing, Liu Jinghui said, "Also, from the perpetrator’s perspective, knowing that much about Xu Li would make them less likely to be someone too familiar to Xu Li. Otherwise, they’d be too easily investigated. Thus, it’s likely the perpetrator isn’t among Xu Li’s close connections."

Jiang Yuan inclined his head, "A casual acquaintance—someone who knows just enough."

"Particularly someone aware of his payday," Liu Jinghui licked his lips and whispered, "This indicates the perpetrator likely interacted with Xu Li, either online or offline, within the past two months."

"Mm."

"I’ve got an idea."

"Oh?"

"Xu Li, as a supermarket stocker, had limited interaction with people. To truly understand him would require time. I think we can run a filter: consider all phones in the same location as Xu Li’s for overlapping durations exceeding three minutes. Let’s see how many suspects we can narrow down."