138: Chapter 134: High-end 138: Chapter 134: High-end Late at night.

Even the owls were asleep.

After hearing Jiang Yuan’s words, the group of technicians found renewed vigor in their work.

In the small courtyard of the scavenger, near the entrance, several technicians gathered together, standing behind Jiang Yuan, listening to him while observing the bloodstains on the ground.

Under the illumination of the floodlights, the color of the blood was somewhat distorted, but the sense of brutality could still be vaguely felt.

The spot Jiang Yuan pointed to was one of the few areas on the ground not covered by objects, with several conspicuous blood spots.

“It doesn’t seem like there are any splash-like bloodstains here either.” Hou Xiaoyong, who had also studied Bloodstain Analysis, was not very proficient and only knew some well-known concepts.

Jiang Yuan only nodded slightly and said, “The books say that splash-like bloodstains often indicate the primary crime scene, the starting point of the attack.

But at today’s scene, the weapon used by the killer clearly lacked lethality, which suggests from another perspective that the killer’s initial intention may not have been to kill.”

Jiang Yuan compared on his own head and then said, “From the cast-off bloodstains around here, one could actually deduce that the assailant used a blunt object, and look at the velocity of the cast-off stains.

It’s clearer on this wall.”

So, everyone turned to examine the bloodstains on the wall.

On the surface of the wall built with red bricks and cement, the majority of the bloodstains were oval and streak shaped, with some fine blood spots in front of them.

“These are characteristics of relatively high-speed bloodstains, suggesting that the blunt object was not very heavy but likely quite long,” Jiang Yuan analyzed as he observed.

The technicians nodded along, indicating they knew these widely understood concepts.

“So, the first strike might not have caused bleeding.

Nor did it produce splash-like patterns,” Jiang Yuan glanced at Hou Xiaoyong, answering his question.

Hou Xiaoyong nodded slowly in understanding.

Indeed, if one is hit on the head with a blunt object, it doesn’t necessarily bleed immediately.

“However, after being struck, Zhang Hong, the scavenger who died, did attempt to escape.

The handprint here with blood on it was pressed onto later, showing that he moved forward abruptly,” Jiang Yuan explained and pointed forward, “The appearance of cast-off patterns here indicates that the second blow broke the scalp.”

Jiang Yuan took two more steps forward, and in front of him was a pile of collapsed items.

“This is where the seventh blow left its mark.

Take photos first, collect the bloodstain evidence, and the rest can be gathered slowly and put aside for later,” Jiang Yuan waved his hand in front of him, marking a specific area.

Hou Xiaoyong and the others, who had been following Jiang Yuan to learn about crime scene reconstruction, were perplexed.

“You ask.”

“You ask.”

The technicians exchanged glances with each other.

A senior technician, tired of passing glances back and forth, gave a stern look with fiery eyes, signaling everyone with a glare, “Are you going to ask, or not?

If you don’t, I’m not dealing with it.

What are you pretending for?

Who will answer when you’re asked later?”

Hou Xiaoyong sighed and voiced his query, “Doctor Jiang, what do you mean by the seventh strike?”

“It means that according to my judgment of the sequence of blows at the crime scene, this is where the seventh strike occurred,” Jiang Yuan replied.

Hou Xiaoyong’s eyes widened, “Didn’t we just say that there was no bleeding from the first strike, and the second strike caused bleeding?

It should be the third strike next, right?”

“The bloodstain from the third strike, I estimate, is on the ground; it has to be lifted to be seen,” Jiang Yuan answered.

This response was actually understandable to everyone.

When the elderly man entered the door, the shelf was intact, and everything was properly placed on it.

It was through the attacker’s assaults and the victim’s evasion that a large number of items fell from the temporary and unsteady shelf.

So, the bloodstain from the third strike got buried under items, which anyone could figure out.

What was different was how Jiang Yuan determined that the topmost was from the seventh strike.

Hou Xiaoyong held back for a few seconds, but still felt he couldn’t restrain himself and asked, “Never mind the third strike’s bloodstain, but how can you be so sure that the top one is the seventh strike and not the sixth or the tenth?”

Jiang Yuan smiled warmly and softly said, “I counted them out.

I had completed the crime scene reconstruction in my mind before explaining it to everyone.”

Hou Xiaoyong was dumbfounded.

Perhaps the fatigue from staying up too long was dulling his judgment and intelligence.

If he could get 8-10 hours of sleep, he felt he could certainly reconstruct several steps as well.

However, this is precisely the misunderstanding all difficult problems present to poor students.

Watching a teacher or someone else’s problem-solving steps, students who follow along step by step, tend to fall into the illusion that they have learned.

But, in fact, students who follow the steps sequentially are still very far from truly learning.

Most math problems are not solved in a step-by-step fashion, but by first looking at the requirements at the end or middle, and then figuring out how to meet them with the preceding steps.

Crime scene reconstruction is similar; no expert in Bloodstain Analysis actually guesses where the first and second steps are.

It would be too foolish and create too much unnecessary burden.

Like the first step, according to what Hou Xiaoyong learned, it seems necessary to look for splash-like bloodstains, but as per Jiang Yuan’s judgment, the first strike didn’t produce any bleeding.

How to proceed then?

And as for the second step, if one needed to find the second strike, would it be viable to analyze each and every bloodstain?

That would require eliminating the possibility of other bloodstains being the second strike.

It’s too troublesome and unnecessary.

The correct approach is to first determine whether the bloodstains are from the early stage, the middle stage, or the late stage, or whether they occurred before or after a landmark event.

Positioning the definite bloodstains first and then gradually filling in the rest is the relatively clear step in solving the puzzle.

However, this sort of thing is like a crossword puzzle; it requires an overall control.

To some extent, if you cannot completely reconstruct a crime scene, you won’t be able to reconstruct even half of it.

Hou Xiaoyong and other technicians, in fact, have not received training in crime scene reconstruction.

Domestic forensic science personnel currently have many ways to learn.

The most common but most basic is the curriculum in schools, which is fundamental.

Although it might not be used in practice, not learning it severely limits the potential for further development.

For example, Bloodstain Analysis would involve some high school physics and chemistry knowledge, such as momentum and angular velocity, which high school students actually spend months and hundreds of problems to understand.

A forensic science technician who has not mastered the necessary knowledge and tries to cram at the last minute is unlikely to understand it at the same level.

Besides the educational methods available after leaving school, reading books and apprentice-style learning at their unit are the two most common patterns.

In addition, various training activities organized by units are gradually becoming the mainstream way for technicians to improve.

Techniques like extracting DNA from sweat now sound simple and common.

But these were also vigorously promoted around 2008 and before that, not only were the technicians unable to perform it, but the DNA laboratory’s equipment and reagents might not have supported it either.

Something like reconstructing a crime scene belongs to a more high-end level; aside from seeking a master to teach you, it’s pretty hard to self-learn through the other methods mentioned.

That’s why TV series keep on showing it, because it seems impressive.

Basic forms of Bloodstain Analysis are indeed touched upon during training, but Hou Xiaoyong and the others are not particularly studious types.

Overall, when Jiang Yuan announced that he had completed the crime scene reconstruction, the technicians all fell into deep thought.

Most of them wondered: how is he planning to fool us?

Jiang Yuan waved his hand and said, “Take another layer off here.”

The technicians, all silent, put on their gloves and removed another layer.

“Still not there, take off one more layer.”

They followed suit.

The pressure from the stack of items was immense, akin to dealing with three girlfriends who find you all at once.

“This should be where the third strike left its mark.” Jiang Yuan also made a note in his notebook.

People glanced over, not understanding, but could only trust Jiang Yuan.

If you can’t mentally calculate 857 divided by 648 and come up with an answer, then you’re forced to accept the result that someone else suggests.

“This is where the strikes happened in the later stage.”

“The position of the bleeding is very particular.”

“From here, the perpetrator entered an excited state.”

Jiang Yuan intermittently described the crime scene, and unlike a performance, his most important task at the moment was evidence collection.

As they continued like this, a tiny blood spot caught Jiang Yuan’s attention.

“Wait,” Jiang Yuan stopped a technician who was about to step forward.

“What’s wrong?”

“This blood spot, if you look at where it landed and its velocity, it’s not from the same event as the other nearby blood spots,” Jiang Yuan noted by just glancing at it.

At this moment, the other technicians looked somewhat bewildered and blank.

They saw no difference; it looked exactly the same…

“All the blood spots have trajectories that are basically parabolic in the air.

If this blood spot came from the victim, it might have taken a smaller angle.”

As Jiang Yuan spoke, he had several photos taken of it.

“You suspect this is from the perpetrator?” Hou Xiaoyong caught the implication.

“At least it is blood that splattered onto the perpetrator and then splashed out.

But most likely, it’s the perpetrator’s own,” replied Jiang Yuan as he carefully collected the blood spot in front of him.

Hearing him say this caused a stir among the other technicians, who once again gathered around to watch.

“The perpetrator was injured?

How did that happen?” Hou Xiaoyong asked anxiously.

Jiang Yuan glanced at him and said in a low voice, “During the crime, the victim might have fought back, maybe something splashed up and hit somewhere, or perhaps the weapon injured the perpetrator…

Jiang Yuan did not intend to explain; to him, a drop of blood could determine many things, and there was no need to find fault.

If someone left a bloodstain at the scene of a violent crime, they should explain the situation at the police station no matter who they are!