civil forensic

Chapter 129 Blood Stain Analysis

As a forensic doctor, even a young forensic doctor, Jiang Yuan gradually became immune to the unpleasant smell of the scene.

Standing at the scene, taking a deep breath, is more of a feeling.

Speaking of which, this was the first time Jiang Yuan had experienced a bloodstained scene.Although no one was dead, Jiang Yuan felt refreshed at first glance.

This is the first time I have used LV5's bloodstain analysis.

"Jiang Yuan, what do you see?" Wu Jun put on his mask and coughed.He also knew that this was the first time Jiang Yuan had experienced a bloodstained scene, so he had to make sure that Jiang Yuan was in a normal state.

In addition, Wu Jun is also going to see Jiang Yuan's understanding of the blood scene. Anyway, he is a newcomer in the field of forensic medicine. It is normal for him to have something he doesn't understand.

When Jiang Yuan was asked, he didn't think too much, and looked around the scene to confirm his thoughts. Then, pointing to the pool of blood, he said, "The wounded bleeding was a lot, and a column of blood stains formed in front of the steps of the house. Therefore, preliminary It can be considered that this is the position where the injured temporarily lie down after being injured."

Wu Jun nodded, this is a basic judgment, and it is the same judgment method for another dead person.

Jiang Yuan also took a photo with his mobile phone and said: "The blood around the blood pool has dried, and the middle is concentrated blood. Judging from the dryness of the blood pool, the time when the wounded bled was about 4 hours ago."

If this is a murder case, the time of death can also be calculated in the same way.

While talking, Jiang Yuan made simple records in a paper notebook, so as not to forget it later, it would be funny—something like this happened to a forensic doctor, and it was really a nightmare in the middle of the night. Even when the person sits up... it's just as scary.

Wu Jun nodded again.The judgment of the time of death has always been the core of forensic skills, and various theories and academic directions will automatically extend in this direction.

Theoretically, when a forensic doctor picks up a branch at the scene, he will think, how can I use it to judge the time of death of the deceased, and the great thing is that it can really be used to judge the time of death.

Of course, the current pool of blood is not very meaningful for judging the time, because the injured are still alive, and the reporter's report is considered positive, so there is basically no doubt about the time of the incident.

However, for forensic doctors, every bit of information at the scene is extremely rare, and those who can make judgments must make judgments.

Then, Jiang Yuan focused on the shape of the bloodstain.

In bloodstain analysis, the shape of the bloodstain is more important than the content of the bloodstain.

In practice, it is the same.

Bloodstain has the effect of traveling through time and space, which can be said to be the closest technology to Sherlock Holmes.

At the scene of a violent crime, when there is a lot of blood, it often means that technicians can reconstruct the crime scene from this.This reconstruction is not a reconstruction in name, but can really reconstruct every step of the victim by the perpetrator, and even every step of the victim before shed blood.

Like at this moment, Jiang Yuan was the first to go to the place where the blood was splattered.

The splattered blood, as the name suggests, is the state of spraying onto the object and then splashing away.

If you are really curious, you can try not to find the toilet when you have blood in your stool, but solve it on the spot. The resulting bloody stool has the characteristic of splashing.

In bloodstain analysis, splatters of blood are usually not from blood in the stool - as we all know.

It often arises from a ruptured arterial vessel and is therefore considered the initial site of injury.

Therefore, when doing bloodstain analysis, or if you want to travel through time and space and reconstruct the scene like a detective, you should start with the splattered bloodstains.

For Jiang Yuan, LV5's bloodstain analysis is a good skill for reconstructing the scene, so he first came to the location of the splattered bloodstain, then looked around, and couldn't help...smiling.

Because looking from his position, he happened to see a few dripping blood droplets, right next to the flower bed not far from the splattering bloodstains.

Jiang Yuan walked over immediately.

This location is slightly away from the bloodstains of Da Tan.And the dripping blood drop is almost a perfect circle, without any small tail...

A drop of blood with a small tail, like a tadpole, or a drop with a longer tail, like a comet, all show one thing, the drop of blood fell on the surface at a certain angle.A blood drop with a longer tail means it hit the surface at a smaller angle.

It is like a blood drop like a comet with a long tail. It usually hits the surface of the object at an angle of less than 30 degrees.

The blood drop without a tail, which is the blood drop Jiang Yuan was looking at, fell vertically.

It is conceivable that in an intense crime scene, under what circumstances would there be bloodstains falling vertically?
It is when blood drops fall from a static person or object that such perfectly round dripping blood drops are formed.

The victim was being chopped off, his hands were broken, and he was lying in a pool of blood, gasping for breath. There was no time to calm himself down, and then the blood dripped down vertically.

Furthermore, the quantity is also different.

Therefore, the dripping blood droplets most likely came from the murderer.

Jiang Yuan made a further judgment, because the dripping blood drops were not continuous, but just a few drops, so it didn't look like the blood was brought from the victim.

In other words, the dripping blood under his feet probably came from the murderer himself.

That's why Jiang Yuan laughed out loud.

Good thing you're wearing a mask.

Sometimes, or in other words, most cases, it may not be so complicated to reconstruct the scene.

Jiang Yuan squatted down, first carefully took pictures, then took a cotton swab dipped in blood, wrapped the cotton swab with filter paper, and folded it into a triangle. This is his usual practice, and all the surveyors around him have seen it. They all turned their heads away.

"Young man, you have good eyesight." Wu Jun walked over and said something with emotion.

He could also tell that this was basically the bloodstain left by the murderer. In other words, with these few drops of blood, the case was basically solved.

Crime of passion, in the face of modern technology, is so simple and direct.

As for why the murderer left bloodstains, this actually involves a question of experience.In fact, similar situations will appear in many crime scenes. A brief overview is still a matter of experience.

For a murderer who kills or stabs someone for the first time, it is usually difficult to estimate how much the force feedback will be when the knife is cut out.

In addition, the weapons used were often inappropriate, and it was extremely tense at the time, and it was very common to injure yourself due to improper force.Moreover, because of the effect of adrenaline, the injured will not feel the pain, so that the cleaning of the scene is ignored.

The reason why the police always emphasize the first scene in solving crimes is because at the first scene, the murderer often leaves a loophole.

And when serial murders are uncovered, why I always like to find the scene where the murderer kills for the first time, because that is the place where the murderer is most inexperienced, and it is also the place where he is most likely to show his flaws.

Similarly, the reason why animal cruelty is always noticed by the police and recorded in foreign countries is because it is often closely related to violent crimes, and it is likely that a murderer is doing self-cultivation.

"From the blood drop, what can you tell?" Wu Jun continued to inspect Jiang Yuan, wanting to see if his understanding of bloodstain analysis was qualified.

Jiang Yuan looked down at the other drops of blood, and said slowly: "From the size of the blood drop, the height of the drop is about one meter. It may be that the murderer's arm fell from the position of the finger after hanging down."

"Well, the judgment is quite accurate. The size of the blood drop is actually not very easy to judge. The difference between a blood drop of one meter and 1.2 meters is not too obvious." Wu Jun said his own experience.

The higher the place, the bigger the drop of blood will be, but because the hand of an ordinary person hangs down, it is just about one meter, so the drop of blood of this size is more concerned.

The 1.2-meter blood drop indicates that the injured part is higher, or the murderer's height is different from ordinary people.

With Jiang Yuan's current ability, it is really easy to judge the height of the blood drop, and said easily: "The blood drop falling at a height of one meter is exactly the cross-sectional size of a straw like Starbucks."

Wu Jun was taken aback, what would a forensic doctor who had never drunk Starbucks do?Fortunately, he knew the size of a drop of blood falling from one meter, so he imagined the cross-sectional area of ​​Starbucks straws in his mind, nodded and said: "The Starbucks straws are quite thick, I thought they were all like the old AD calcium. What about milk?"

Jiang Yuan understood, and said, "Let's get someone to bring Starbucks over from Changyang City, and let's work on the case while drinking coffee."

Wu Jun nodded in agreement, and said again: "Yes, when the time comes, we will drink coffee and smoke Zhonghua, and educate this murderer well."

Just as he was talking, a criminal policeman led someone to the gate of the yard, and shouted inside: "The victim's family members are here."

Jiang Yuan and Wu Jun looked over and saw a man in his forties following behind the criminal policeman, his right hand still wrapped in gauze.

The two couldn't help but their eyes lit up.

Wu Jun first winked at the two criminal policemen standing next to him, waited for the two criminal policemen to leave the courtyard, walked a few steps forward, and after reaching behind the man, Wu Jun casually asked the man, "Why are you injured?"

The man said hoarsely, "I fought with the gangster and got hurt."

"This is the victim's husband. He was bandaged at a relative's house next door." The criminal policeman who brought him over saw this posture and understood it. While talking, he grabbed the man's injured arm, as if showing it to everyone, and Said: "The injury is not too serious, there is a little blood."

Wu Jun nodded, and asked again: "Where did you fight?"

"Just... just that..." The man pointed to the location, which was near the flower bed.

"Then how did you get hurt?"

"The other party picked up a hatchet to chop, and I blocked it."

"Where is it blocked?"

"That's right there." The man was still pointing to the flower bed.

Both Wu Jun and Jiang Yuan smiled, and they didn't have any splash injuries. Are you ashamed to say that you blocked the knife?

(End of this chapter)