Diary of a Criminal Investigator-Chapter 290: Collecting Physical Evidence

Afterwards, the three of them had a detailed discussion of the entire reasoning process and confirmed that there were essentially no logical flaws.

As technical staff in the Crime Scene Investigation of the Criminal Investigation Team, both Old Bai and Yang Sen, although they had previously worked in criminal investigations and were frontline detectives, had transitioned roles about ten or twenty years ago.

Over the years, they became more familiar with technology rather than frontline investigative work.

So, although they made some discoveries, they still analyzed for a long time before finally concluding that there was nothing wrong with the recent deduction.

Lu Chuan was even more remarkable. In terms of criminal investigation technology alone, Lu Chuan was the top choice in the Criminal Investigation Team of Haizhou City, even within the entire City Public Security Bureau, but he basically had no frontline investigative experience.

"Alright, Brother Yang, Brother Bai, you go report, I’ll head to the Forensic Doctor’s side."

"Hey, hey, for such reporting matters, you young people should go," Yang Sen shook his head and waved his hand, "Old Bai is going to retire in a few years, and I’m at this age with no promotion prospects. Lu, you should make more rounds with the leaders." 𝒇𝒓𝒆𝒆𝙬𝒆𝒃𝓷𝒐𝓿𝙚𝙡.𝒄𝓸𝒎

"Right, right, even though Old Yang discovered this first, it was verified by the three of us together. Lu, you go report."

Old Bai said this and pushed Lu Chuan out of the office door.

Lu Chuan couldn’t resist them and had to go report.

The case analysis meeting in the conference room was still ongoing, and this news should be able to provide everyone with more clues.

Gently pushing open the conference room door, although it didn’t make any noise, as soon as everyone turned around and saw it was Lu Chuan, even Qin Yong, who was arranging tasks, stopped.

Qin Yong was already very familiar with Lu Chuan.

Capable, tactful, intelligent, and wealthy.

Here they were in a case analysis meeting, and Lu Chuan suddenly came in, surely there was a discovery.

"Lu, does CSI have any new findings?"

Lu Chuan, initially a bit embarrassed by everyone’s gaze, immediately nodded when he heard Qin Yong speak, "Yang Sen found a detail while scanning the CSI photos."

Lu Chuan knew that Old Yang and Old Bai had let him come to report for his own good.

But to be fair, in terms of merit alone, Lu Chuan didn’t really lack it this time either.

Relatively speaking, it was just an additional opportunity to show face.

Lu Chuan couldn’t refuse, but he would never hide the fact that Old Yang made the discovery.

"Oh? Let’s hear it."

"Yes!"

Yang Sen, along with the others, not only discussed this in the relevant office but also recorded a short video for demonstration.

"The deceased’s shoelaces on both feet were tied in a criss-cross butterfly style, but the indentation directions of the bow knots were inconsistent..."

Lu Chuan detailed the recent discovery and played a video of the verification process for everyone to see.

Those in the meeting room wearing sneakers couldn’t help but try it themselves.

"Indeed, it is so."

"Hmm, I tried it too. It’s true that with the indentation direction, doing it this way results in a difference."

"So, we believe that one of the deceased’s shoelaces may have been tied by someone else, and this person is likely the murderer."

"Later, I’ll go to the Forensic Doctor’s office to see if any information can be extracted from the deceased’s shoelaces."

The discovery from CSI further corroborated the results of the forensic autopsy report.

The deceased’s death was not a simple traffic accident.

However, the key lies in the work Lu Chuan is preparing to undertake.

If useful information can be extracted from the shoelaces, there could be a breakthrough in solving the case.

Morgue.

Because the body was relatively fresh, there was no foul smell, just the normal scent of blood, so Forensic Doctor Shen didn’t need heavy-duty protective gear like a gas mask.

Wearing triple-layer gloves and multiple-layer masks was sufficient.

The body had already been placed in the refrigerated cabinet, and the deceased’s clothing had yet to be organized.

"The shoes are here."

Shen Yan picked up the shoe by the tip and, along with Lu Chuan, placed both shoes in a large evidence collection bag.

"Any discoveries?"

Lu Chuan shook his head, "That’s uncertain."

"Someone has touched the deceased’s shoelaces, but for now it seems there’s no problem, and it’s hard to determine if this person is the murderer."

"But the likelihood of them being the murderer is high."

"Moreover, if the other person only touched the shoelaces, it’s uncertain if they’ve left any biological traces."

"If the person was wearing gloves, this clue might be useless."

"Alright, you get busy then. I’ll organize these and call me if you need anything."

"Okay, I’ll start the experiments."

CSI underground laboratory.

Lu Chuan was collecting trace substances from the shoelaces.

First, fingerprints.

If the murderer didn’t wear gloves, they’d definitely leave fingerprints on the shoelaces when tying them.

However, extracting fingerprints from cotton or linen materials isn’t simple.

Lu Chuan first used an ultraviolet lamp to examine them; discoveries were on both shoelaces.

But having discoveries doesn’t mean they’re the murderer’s fingerprints; they could also be from the deceased, and they likely would leave fingerprints on the shoelaces.

Extracting fingerprints from cotton or linen is typically difficult using chemical methods.

After fixing the ultraviolet lamp, Lu Chuan extracted some fingerprints through photography.

Of course, the quality of these fingerprints could only be described as fragmented.

Since the shoelace’s width is only about half a centimeter, coupled with the force applied when tying, the deformation of fingerprints is severe.

These fingerprints won’t provide enough characteristic points to be used as legal evidence; they can only assist in identity confirmation.

The fingerprint extraction was quick; the difficult part was the subsequent identification and analysis.

Lu Chuan didn’t directly go into analysis but continued collecting other trace evidence.

No matter if the person wore gloves while tying the shoelaces, they’d leave materials on the surface of the laces.

It could be skin flakes or rubber or fibers from the gloves.

Actually, the likelihood of the murderer wearing gloves while tying shoelaces is relatively low; tying shoelaces is an involuntary action, but it’s a fine task.

Handling it with gloves would be uncomfortable or even if tied, it might not achieve the desired effect.

For collecting trace evidence, Lu Chuan wasn’t using the ultraviolet lamp but switched to a multi-frequency spectrometer.

Adjusting the light wave length, he began scanning.

Light waves of different frequencies are useful for identifying different biological traces.

Skin flakes, hair, fibers—all have their strongly reactive spectral bands.

Skin flakes, for example, reflect purple light under 400-nanometer light waves; even tiny micrograms can be detected.

This is a meticulous job. It took Lu Chuan over two hours with both pairs of shoes plus the shoelaces.

Meanwhile, the investigative and action teams were also advancing their investigation work.