Chapter 291: Extracting Physical Evidence
After that, the three discussed the entire reasoning process in detail and confirmed that there were basically no logical loopholes.
As on-the-spot investigation technicians of the criminal investigation detachment, both Lao Bai and Yang Sen have worked in criminal investigations before and are front-line criminal police officers, but after all, they have been transferred to other positions for more than ten or twenty years.
After so many years, they are more familiar with technology rather than front-line investigation work.
So a few people made some discoveries, but they still analyzed it for a long time before finally confirming that there was nothing wrong with the reasoning just now.
Not to mention Lu Chuan, in terms of criminal investigation technology alone, Lu Chuan can be regarded as the number one in the entire Haizhou City Criminal Investigation Detachment and even the Haizhou City Public Security Bureau, but he basically has no experience in front-line criminal investigation.
"Well, Brother Yang, Brother Bai, you go report it, and I'll go to the forensic doctor."
"Alas, you young people should go and report this kind of thing," Yang Sen shook his head Waving his hand: "Lao Bai will retire in a few years. I am at this age and there is no hope of promotion. Xiao Lu, please go to the leader more often."
"Yes, yes, although this is Lao Yang discovered it first, but it was also verified by the three of us. Xiao Lu, you go and report it. "
Lao Bai said, pushing Lu Chuan out of the office door.
Lu Chuan couldn't survive them, so he had to report first.
The case analysis meeting in the conference room has not ended yet. Just in time, this news should give everyone more clues.
The door of the conference room was gently pushed open. Although no sound was made, when everyone turned around and saw that it was Lu Chuan, even Qin Yong who was arranging work stopped.
Qin Yong can be said to already know Lu Chuan very well.
Ability, sense, brains, and money.
A case analysis meeting was being held here. Lu Chuan suddenly came in. He must have discovered something.
"Xiao Lu, are there any new discoveries in the current survey?"
Lu Chuan was a little embarrassed by everyone, but he nodded immediately when he heard Qin Yong speak: "Yang Sen was just here When scanning the photos, I discovered a detail. "
Lu Chuan knew that Lao Yang and Lao Bai asked him to report for his own benefit.
But one is one and two is two. In terms of merit alone, Lu Chuan is actually not bad at all.
Relatively speaking, it's just one more chance to show off.
Lu Chuan couldn't refuse, but he would never hide the fact that Lao Yang had discovered it.
"Oh? Tell me."
"Yes!"
The three of Yang Sen not only discussed it in the relevant office, but also recorded it with their mobile phones for the convenience of display. A short video.
"Although the shoelaces of the deceased's left and right feet are tied in a criss-cross butterfly shape, the left and right indentations of the two shoelaces are in inconsistent directions..."
Lu Chuan introduced the findings just now in detail, and passed The video shows the verification of several people for everyone.
Some of the people in the conference room wore sneakers and couldn't help but try it out themselves.
“That’s true.”
“Well, I tried it too, and it’s true that the direction of the indentation will be different if I do it this way.”
"So, we believe that one of the deceased's shoelaces may have been tied by someone else, and this person is most likely the murderer."
"Later, I went to the medical examiner's office to see Let’s see if we can extract some information from the deceased’s shoelaces.”
This discovery further supports the results of the forensic autopsy report.
The death of the deceased was not a simple traffic accident.
However, the most critical thing is actually the work Lu Chuan is preparing to do.
If useful information can be extracted from the shoelaces, a breakthrough may be made in solving the case.
Autopsy room.
Because the corpse is relatively fresh and has no strange smell, only the normal smell of blood, forensic doctor Shen naturally does not need to be fully equipped such as a gas mask.
Just wear three layers of gloves and a multi-layer mask.
The body had been put into the refrigerator, and the clothes the deceased was wearing had not yet been packed away. "Here are the shoes."
Shen Yan held the tips of her shoes and put the two shoes into a large evidence collection bag with Lu Chuan.
“Can anything be found?”
Lu Chuan shook his head: “I’m not sure.”
“Someone has touched the shoelaces of the deceased, but at present there should be no What’s the problem, and it’s still unclear whether this person is the murderer.”
"It's just that the probability of being the murderer is very high."
"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 has only touched the shoelaces, it is hard to say." Wearing gloves, this clue is probably useless."
"Well, you go ahead and I'll put these away. Call me if you need anything."
"Okay. , I’ll do the experiment first.”
Underground laboratory currently under investigation.
Lu Chuan is collecting trace substances from shoelaces.
The first is fingerprints.
If the murderer did not wear gloves, he would definitely leave fingerprints on the shoelaces while tying them.
However, extracting fingerprints from cotton and linen materials is not simple.
Lu Chuan first irradiated it with ultraviolet light and found it on both shoelaces.
But the discovery does not mean that the fingerprints are those of the murderer. It is also possible that the deceased's own fingerprints will be left on the shoelaces.
Fingerprint extraction on cotton and linen materials is generally difficult to use chemical development.
After Lu Chuan fixed the ultraviolet lamp, he extracted some fingerprints by taking photos.
Of course, the quality of these fingerprints can only be described as fragmented.
After all, the width of the shoelaces itself is only about half a centimeter. When tying shoelaces, your fingers will be harder, and the deformation of fingerprints will be very serious.
These fingerprints are destined to be impossible to collect enough characteristic points to become judicial evidence, and can only play a role in assisting in determining identity.
Fingerprint extraction is very fast, but the difficult part is the subsequent identification analysis.
Lu Chuan did not analyze it directly, but continued to collect other trace evidence.
No matter whether the other party wore gloves to tie the deceased's shoelaces or not, substances would be left on the surface of the shoelaces.
It could be skin flakes, or it could be rubber or fibers on the gloves.
In fact, the possibility of the murderer wearing gloves to tie his 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 wave length and start scanning.
Light waves of different frequencies can be suitable for discovering different biological traces.
Dander, hair, fiber, each substance has its own corresponding spectral band with strong reaction.
For example, dandruff can reflect purple light under the light wave of 400 nanometers, and dandruff of a few micrograms can be detected.
This was a delicate job. It took Lu Chuan more than two hours to work on two pairs of shoes and shoelaces.
At the same time, the map detective and action teams are also advancing investigation work.
(End of this chapter)