Late at night.

Even the owls were asleep.

After listening to Jiang Yuan's words, the technicians regained their enthusiasm.

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

Under the illumination of the headlights, the color of the blood was slightly distorted, but the cruelty within could still be vaguely felt.

The position of Jiang Yuan's fingers was one of the few areas in the courtyard that was not covered by objects, and the bloodstains in several places were quite conspicuous.

"It seems that there are no splatter bloodstains here either." Hou Xiaoyong had also studied bloodstain analysis, but he only knew some well-known knowledge and was not very proficient.

Jiang Yuan just nodded slightly and said, "According to the book, splatter bloodstains often indicate the first crime scene, the initial location of the perpetrator. But in today's crime scene, the weapon used by the killer obviously lacked sufficient lethality, which indicates that the killer's initial intention may not have been murder."

Jiang Yuan compared it in his mind and continued, "From the splatter bloodstains around, it can actually be seen that the killer should have used a blunt weapon, and also, look at the speed of the splatter bloodstains. It is more obvious on the wall over here."

Everyone then gathered around to look at the bloodstains on the wall.

On the wall made of red bricks mixed with cement, oval and elongated bloodstains were predominant, with some small bloodstains in front.

"These are characteristics of relatively high-speed bloodstains, indicating that the blunt weapon is not heavy and may be relatively long." Jiang Yuan analyzed while looking.

Several technicians nodded, indicating that they knew this well-known knowledge.

"So, his first strike may not have caused bleeding. There were no splatter bloodstains either." Jiang Yuan looked at Hou Xiaoyong and answered his question.

Hou Xiaoyong nodded slowly as he listened.

Indeed, if you hit someone on the head with a blunt object, it wouldn't immediately cause bleeding.

"But after being hit, Zhang Hong, the scavenger who died, made an evasive movement. The blood on the fingerprints here was pressed later, indicating that he moved forward." Jiang Yuan pointed forward and said, "The splatter bloodstains here indicate that the second strike broke the scalp."

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

"This is the mark left by the seventh strike. Take a photo of it first, collect the bloodstain evidence, and the rest can be collected later." Jiang Yuan waved his hand in front, marking out a section.

Hou Xiaoyong and the others who were preparing to learn how to reconstruct the crime scene were stunned and a bit at a loss.

"You ask."

"You ask."

A quick look at bit.ly/3iBfjkV will leave you more fulfilled.

Several technicians exchanged glances.

The senior technician who had exchanged glances with others for a long time directly glared at everyone, indicating, "Are you going to ask or not? If you don't ask, I won't bother. What are you pretending for? When you're asked later, who will answer?"

Hou Xiaoyong sighed and asked, "Forensic Jiang, what does the seventh strike mean?"

"It means that I judged it according to the order of the strikes at the crime scene. This is the mark left by the seventh strike." Jiang Yuan answered.

Hou Xiaoyong widened his eyes and said, "Didn't we just say that there was no bleeding in the first strike, then bleeding in the second strike, and then there should be the third strike."

"The bloodstains from the third strike, I estimate, are on the ground. We need to lift it up to see." Jiang Yuan replied.

This answer could actually be understood by everyone.

When the old man entered the room, the shelf was still intact, and the items were placed properly on the shelf. It was only during the attacker's attack and the victim's escape process that a large number of objects fell from the temporary and unstable shelf.

Therefore, the bloodstains from the third strike were buried by the objects above, which anyone could understand.

The difference was how Jiang Yuan determined that the topmost one was the mark left by the seventh strike.

Hou Xiaoyong endured for a few seconds but couldn't bear it anymore, and asked, "As for the bloodstains from the third strike, let's not talk about it for now. How can you say that the one on top is the seventh strike and not the sixth or tenth?"

Jiang Yuan smiled gently and said softly, "I counted it. I have already completed the reconstruction of the crime scene in my mind before telling you all."

Hou Xiaoyong was instantly stunned.

It was also because he had been staying up too late, causing his judgment and intelligence to decline.

If he could sleep for 10 or 8 hours, he believed he could also reconstruct a few steps.

However, this was actually a misunderstanding given to mediocre students by all difficult problems.

Students who followed the teacher's or others' solution steps step by step often had a misconception that they had learned it.

In fact, students who followed the steps in order were still far from truly understanding.

Most math problems are not solved step by step, but by first looking at the requirements at the end or in the middle, and then seeing how to achieve those requirements from the beginning.

Just like reconstructing a crime scene, no bloodstain analysis expert really guesses where the first step is, where the second step is, and so on, step by step.

Doing it this way is too foolish and creates unnecessary burdens for oneself.Just like the first step, according to the information Hou Xiaoyong learned, it seemed that they should look for splattered bloodstains. However, according to Jiang Yuan's judgment, the first strike didn't draw blood. How could this be?

And for Jiang Yuan's second step, it was similar. If they were to find the second strike, should they look through each bloodstain and analyze them? Then they would have to rule out the possibility that other bloodstains were from the second strike.

Too troublesome and unnecessary.

The correct approach was to first determine whether the bloodstains were from the early, middle, or late stages of the incident, or whether they were before or after a significant event.

Once the bloodstains were properly placed, the remaining ones could be filled in slowly. This was a relatively straightforward way to solve the puzzle.

However, this was like a crossword puzzle, requiring an overall control. To some extent, if one couldn't fully reconstruct the crime scene, they wouldn't be able to construct half of it.

Technicians like Hou Xiaoyong had never received training in reconstructing crime scenes.

Currently, there were many ways for criminal science technicians in China to learn. The most common and basic one was through school courses. These were the basics of the basics. They might not be used in practice, but if they weren't learned, the potential for future development would be very low.

For example, bloodstain analysis would involve some high school physics and chemistry knowledge, such as momentum, angular velocity, and so on. High school students would need to spend several months and solve hundreds of problems to understand these concepts.

A criminal science technician who didn't master the relevant knowledge would not be able to understand it at the same level by cramming at the last minute.

Besides school, reading books and learning from masters in the unit were the two most common methods.

In addition, various training activities organized by different units had gradually become the mainstream for technicians to improve their skills.

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

But this was only after it was vigorously promoted around 2008. Before that, not only did the technicians not know how to do it, but the equipment and reagents in the DNA laboratory might not support it.

Reconstructing a crime scene was considered too advanced. Except for learning from a master, it was basically difficult to practice on one's own.

That's why TV shows often portrayed it, because it seemed impressive.

Basic bloodstain analysis and the like would be mentioned during training. However, Hou Xiaoyong and others were not particularly good learners.

In general, when Jiang Yuan said he had completed the reconstruction of the crime scene, several technicians fell into deep thought.

Most of them were thinking: How is he going to fool us?

Jiang Yuan waved his hand and said, "Take another layer here."

The technicians, without a word, put on their gloves and took another layer of objects.

"Not yet, then take another layer."

Everyone followed suit.

The pressure brought by the stacked objects to the technicians was no less than having three girlfriends at the same time, all coming to find them.

"This should be the trace of the third strike." Jiang Yuan also made a note on his notebook.

Several people looked over, not understanding, but could only trust Jiang Yuan.

If you can't calculate 857 divided by 648, then when you hear the result from others, you can only accept it.

"This is the position of the later strikes."

"The position of the bleeding is very particular."

"From here, the murderer entered an excited state."

Jiang Yuan intermittently described the crime scene. Unlike a performance, his most important job now was to collect evidence.

As they dug, a tiny blood spot caught Jiang Yuan's attention.

"Wait." Jiang Yuan stopped the technician who was about to step forward.

"What's wrong?"

"This blood spot, look at its landing point and speed, it's not the same as the other blood spots nearby." Jiang Yuan noticed this blood spot with a glance.

At this moment, the other technicians were somewhat dazed.

Where is the difference? They all look the same...

"All the blood spots, their trajectory in the air, are basically a parabola. This blood spot, if it comes from the victim, it is likely to cut a smaller angle."

As Jiang Yuan spoke, he had several photos taken.

"Do you suspect this came from the murderer?" Hou Xiaoyong understood the implication.

"At least it's blood that splashed onto the murderer and then splattered out. But the most likely scenario is that it's the murderer's own."

As Jiang Yuan spoke, he carefully collected the blood spot in front of him.

Hearing him say this, the other technicians were stirred up and gathered around to watch again.

"Did the murderer get hurt? How did he get hurt?" 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 maybe the weapon hurt the murderer..."

Jiang Yuan didn't intend to explain further. For him, a drop of blood was enough to determine many things, and there was no need to be exhaustive.

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