Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

Chapter 291 Extraction Evidence
Afterwards, the three of them discussed the entire reasoning process in detail and confirmed that there were basically no logical loopholes.

As current survey technicians of the Criminal Investigation Detachment, whether it is Lao Bai or Yang Sen, although they have done criminal investigations before, they are all front-line criminal police officers, but after all, they have been transferred for more than ten or twenty years.

After so many years, they are more familiar with technology than front-line investigative work.

So several people made some discoveries, but it took a long time to analyze before finally confirming that there was nothing wrong with the reasoning just now.

Not to mention Lu Chuan, just talking about criminal investigation technology, Lu Chuan can be regarded as the first in the entire Haizhou Criminal Investigation Detachment and even the Haizhou Public Security Bureau, but basically has no experience in front-line criminal investigation.

"Well, Brother Yang, Brother Bai, you go and report, and I'll go to the forensic doctor."

"Alas, report this kind of thing, you young people go," Yang Sen shook his head and waved his hands: "Old Bai retired in a few years, and I am also at this age, there is no hope of promotion, Xiao Lu, you should lead that Let's go."

"Yes, yes, although Lao Yang discovered this first, it was verified by the three of us together. Xiao Lu, you go and report it."

As Lao Bai said, he pushed Lu Chuan out of the office door.

Lu Chuan couldn't survive them, so he could only report first.

The case analysis meeting in the conference room has not yet ended, so this news should bring you one more clue.

Gently pushed open the door of the conference room. Although there was no sound, everyone turned around and saw that it was Lu Chuan. Even Qin Yong, who was arranging work, stopped.

Qin Yong already knew Lu Chuan very well.

Capable, measured, smart, and rich.

There is a case analysis meeting here, and Lu Chuan came in suddenly, so he must have discovered something.

"Little Lu, is there any new discovery over there?"

Lu Chuan was originally a little embarrassed by everyone, but he nodded immediately when he heard Qin Yong's words: "Yang Sen just discovered a detail while scanning the current survey photos."

Lu Chuan knew that Lao Yang and Lao Bai asked him to report for his own good.

But one is one and two is two. In terms of credit alone, Lu Chuan is actually not bad once.

Relatively speaking, it's just one more chance to show your face.

Lu Chuan was not easy to refuse, but he would never hide the fact that this was discovered by Lao Yang.

"Oh? Tell me."

"Yes!"

The three of Yang Sen not only discussed in the relevant office just now, but also recorded a small video with their mobile phone for the convenience of display.

"Although the shoelaces on the left and right feet of the deceased were all tied in a crossed butterfly shape, the left and right indentations of the bows on the two shoelaces were not in the same direction..."

Lu Chuan introduced the discovery just now in detail, and played the verification of several people to everyone through the video.

The people in the conference room, some in sneakers, couldn't resist trying it out for themselves.

"it is as expected."

"Well, I tried it too. It is true that the direction of the indentation will be different if it is done this way."

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

"Later, I'll go to the medical examiner's office to see if I can extract some information from the deceased's shoelaces."

The discovery now under investigation is said to further corroborate the results of the autopsy report of the forensic doctor.

The death of the deceased was not a simple traffic accident.

However, the most important thing is actually the work that Lu Chuan is going to do.

If useful information can be extracted from the shoelaces, a breakthrough may be made in the detection of the case.

Autopsy room.

Because the corpse is relatively fresh, there is no strange smell, only the normal smell of blood, forensic doctor Shen naturally does not need to be fully armed with gas masks.

Just wear three layers of gloves and a multi-layer mask.

The body has been put into the freezer, and the clothes worn by the deceased have not had time to pack.

"Here are the shoes."

Shen Yan lifted the toe of the shoe, and together with Lu Chuan put the two shoes into the large evidence collection bag.

"Can you find anything?"

Lu Chuan shook his head: "This is not sure."

"Someone touched the shoelaces of the deceased, but so far there should be no problem, and it is still uncertain whether this person is the murderer."

"It's just that there is a high probability that it is the murderer."

"In addition, if the other party has only touched the shoelaces, it is hard to say whether there are any biological traces on them."

"If the other party is wearing gloves, this clue is probably useless."

"Well, then you are busy first, I will pack these up, and call me if you need anything."

"Okay, I'll do the experiment first."

The underground laboratory is being investigated.

Lu Chuan is collecting trace substances on shoelaces.

The first is fingerprints.

If the murderer didn't wear gloves, then the process of tying the shoelaces would definitely leave fingerprints on the shoelaces.

However, it is not easy to extract fingerprints on cotton and linen materials.

Lu Chuan first irradiated with ultraviolet light, and both shoelaces were found.

However, it was discovered that this does not mean that the fingerprints belonged to the murderer. The fingerprints of the deceased may also be, and it should be said that they will definitely be left on the shoelaces.

It is generally difficult to extract fingerprints on cotton and linen materials by means of chemical development.

After Lu Chuan fixed the ultraviolet lamp, he took some fingerprints by taking pictures.

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

After all, the width of the shoelace itself is only about half a centimeter, and when tying the shoelace, the fingers will be more forceful, and the deformation of the fingerprint will be very serious.

These fingerprints are destined to be impossible to collect enough feature points to become judicial evidence, and can only play an auxiliary role in determining the identity.

The extraction of fingerprints is very fast, but the difficulty is the follow-up identification analysis.

Lu Chuan did not analyze it directly, but continued to collect other trace evidence.

Regardless of whether the other party wears gloves to tie the shoelaces of the deceased, substances will be left on the surface of the shoelaces.

It could be dander, or it could be rubber or fibers from the glove.

In fact, the possibility of the murderer wearing gloves and tying shoelaces is relatively small. Although the action of tying shoelaces is a subconscious action, it is a relatively delicate job after all.

If you wear gloves to operate, you will be very uncomfortable, or even if you wear them, you will not be able to achieve the desired effect.

To collect trace evidence, Lu Chuan did not use ultraviolet light, but replaced it with a multi-frequency spectrometer.

Adjust the light wavelength length and start scanning.

Light waves of different frequencies can be applied to discover different biological traces.

Dander, hair, fiber, each substance has its own corresponding spectral band with strong reaction.

For example, dander, under the light wave of 400 nanometers, can reflect purple light, and a little bit of a few micrograms of dander can be found.

This is a delicate job. Lu Chuan spent more than two hours on two pairs of shoes and shoelaces.

At the same time, the graphic investigation and action teams are also advancing the investigation work.

(End of this chapter)