131: Chapter 128 Bloodstain Analysis 131: Chapter 128 Bloodstain Analysis As a forensic doctor, even a young one, Jiang Yuan had gradually become immune to the unpleasant odors at crime scenes.

Standing at the scene, taking a deep breath, he felt more a sense of poignancy than disgust.

It was, after all, Jiang Yuan’s first experience with a bloodstain scene.

Though no one had died, a glance at it still invigorated him.

This was also his first time applying LV5 Bloodstain Analysis.

“Jiang Yuan, do you see anything?” Wu Jun had put on his mask and cleared his throat.

He knew it was Jiang Yuan’s first bloodstain scene, so he needed to make sure Jiang Yuan was in a normal state of mind.

Besides, Wu Jun was ready to see how well Jiang Yuan understood bloodstain scenes.

After all, as a newcomer in the forensic field, it was normal to have things to learn.

When asked, Jiang Yuan didn’t overthink it.

He took another look around the scene to confirm his thoughts, then pointed to the pool of blood and said, “The victim lost a significant amount of blood, and the steps leading into the house are stained with what appears to be runoff patterns, which suggests that this may be where the victim lay down after being injured.”

Wu Jun nodded.

That was a basic assessment, and it would be the same even if there had been a fatality.

Jiang Yuan then took a photo with his smartphone, adding, “The blood around the pool has dried, while the center features more congealed blood.

Just from the drying pattern of the bloodstain, the bleeding seems to have occurred approximately four hours prior.”

If this had been a homicide, the time of death could be estimated in a similar manner.

As he spoke, Jiang Yuan jotted down simple notes in a paper notebook, lest he forget later and make a fool of himself—which had actually happened to a forensic doctor before.

It was the stuff of nightmares, more frightening than seeing the victim sit up straight in the morgue.

Wu Jun nodded again.

Estimating the time of death had always been at the heart of forensic skills.

Various theories and academic perspectives would inevitably extend in that direction.

In theory, a forensic doctor could pick up a twig at the scene and think, “How can I use this to determine the time of death?” And the impressive part was that it could indeed be used for that purpose.

Of course, determining the time from the blood pool wasn’t particularly significant in this case, as the victim was still alive, and the person who had reported the crime had done so promptly, leaving little question about when the incident occurred.

However, for a forensic doctor, every bit of information at a scene was highly valuable.

Judgments that could be made undoubtedly had to be made.

Following that, Jiang Yuan focused his attention on the morphology of the bloodstains.

In Bloodstain Analysis, the morphology of bloodstains is more important than the content.

And this held true in practice as well.

Bloodstains have the power to traverse time and space, making them a technology closest to Sherlock Holmes.

At a violent crime scene with a large amount of bloodstains, it often means that technicians could use them to reconstruct the crime scene.

This reconstruction isn’t just in name but an actual re-enactment of every step the offender took towards the victim and every action the victim took before bleeding out.

At this moment, for instance, Jiang Yuan first walked over to where the spatter bloodstains were located.

As the name implies, spatter bloodstains occur when blood shoots out onto an object and then splashes around.

If one is really curious, they could try not using a toilet during a nosebleed and instead let it happen on the spot.

The resultant nosebleed would exhibit spatter characteristics.

But in Bloodstain Analysis, spatter bloodstains usually don’t come from nosebleeds—as everyone knows.

They often originate from ruptured arterial vessels and therefore are considered to indicate the initial position of an attack.

So, to perform Bloodstain Analysis or to reconstruct a scene like a detective who can traverse time and space, one should start with spatter bloodstains.

For Jiang Yuan, LV5 Bloodstain Analysis was the perfect skill for reconstructing the scene.

Hence, he first went to check the spatter bloodstains, looked around, and couldn’t help but smile.

From his position, he could clearly see several drops of blood in a perfect round shape near a flowerbed not far from the spatter.

Jiang Yuan immediately walked over to them.

This spot was slightly away from the large pool of blood.

The droplets were almost perfectly circular without any tails…

Blood droplets with tails, which look like tadpoles or comets with longer tails, indicate one thing: the blood hit the surface at an angle.

The longer the tail of a droplet, the smaller the angle at which it struck the surface.

Just like a comet-tailed droplet, it usually strikes the surface at an angle less than 30 degrees.

But the tailless droplets, like the ones Jiang Yuan was looking at, fell vertically.

One could imagine, at a violent crime scene, under what circumstances would blood fall vertically?

Only when droplets fall from a static person or object will they form such perfect circular droplets.

The victim, being hacked at, even with severed hands and gasping in a pool of blood, would have no opportunity to be still enough to drop blood vertically.

Besides, the volume was different.

Therefore, the tailless droplets most likely came from the perpetrator.

Jiang Yuan further deduced that since the blood droplets on the ground weren’t continuous, but rather just a few droplets, they likely didn’t come from the victim.

In other words, the droplets beneath his feet were very likely to have originated from the murderer himself.

That’s why Jiang Yuan couldn’t help but laugh.

Luckily, he was wearing a mask.

Sometimes, or rather, in the majority of cases, it may not be necessary to reconstruct the scene to such complexity.

Jiang Yuan squatted down, carefully took photos, then used a cotton swab to collect some of the blood, wrapping the cotton in filter paper, folding it into a triangle—his usual practice.

The crime scene investigators around him had all seen this before; at this moment, they all turned their heads away.

“Young man, you really have sharp eyes,” Wu Jun walked over and expressed his admiration.

He too could tell that those were likely blood traces left by the murderer.

In other words, with those few droplets, the case was essentially cracked.

Crimes of passion, when faced with modern technology, are just that simple and direct.

As for why the murderer left behind blood traces, this actually ties into a matter of experience.

In fact, similar situations occur at many crime scenes – to put it simply, it’s an issue of experience.

First-time murderers or those brandishing a weapon often find it difficult to judge the extent of force feedback from their blow.

Moreover, the weapon used is often not suited to the task at hand, coupled with the high stress of the situation, incorrect application of force leading to self-injury is quite common.

Plus, due to the role of adrenaline, the injured person won’t immediately feel pain, leading to neglect in cleaning up the scene.

Why is the primary crime scene always emphasized in police investigations?

It’s because, at the primary scene, the murderer is often prone to slipping up.

And why are the locations of a serial killer’s initial crimes sought out in the resolution of serial homicide cases?

It’s because that’s where the murderer lacks experience and is most likely to reveal flaws.

Similarly, why does cruelty to animals abroad garner police attention and get recorded?

It’s because such acts are often closely linked to violent crimes, and additionally, may represent a killer’s self-training.

“What can you tell from the blood droplets?” Wu Jun continued to probe Jiang Yuan, wanting to see if his understanding of Bloodstain Analysis was up to par.

Jiang Yuan looked down at the other droplets and spoke slowly, “Judging from the size of the droplets, they fell from a height of about one meter.

It’s possible the blood fell from the murderer’s fingertips as his arms hung down.”

“Hmm, quite an accurate judgment.

The size of these droplets is actually not so easy to determine; there’s not much difference between blood droplets falling from one meter to one meter twenty,” Wu Jun shared his experience.

The higher the blood falls from, the larger the droplet becomes, but since the average person’s hands, when hanging down, are just about one meter off the ground, that size of blood droplet receives more attention.

A droplet from one meter twenty suggests a higher injury location, or that the murderer’s height is unusual.

With Jiang Yuan’s current abilities, determining the height from which the blood droplets fell was effortless.

He confidently said, “Blood droplets from one meter resemble the size of a Starbucks straw’s cross-section.”

Wu Jun was taken aback.

How would a forensic doctor who’s never had Starbucks proceed?

Thankfully, he knew the size of a droplet that fell from one meter, so he visualized the cross-sectional area of a Starbucks straw in his mind and nodded, “Those Starbucks straws are quite thick, huh?

I thought they’d all be like those from AD calcium milk from back in the day.”

Jiang Yuan understood and said, “Next time, we’ll have someone bring Starbucks from Changyang City, and we can drink coffee while working on the case.”

Wu Jun nodded in agreement, then added, “Right, we’ll drink coffee and smoke Zhonghua cigarettes while we give the murderer a good lesson.”

While they were talking, a detective brought someone to the entrance of the yard and called out, “The victim’s family member has arrived.”

Jiang Yuan and Wu Jun looked over to see a man in his forties following behind the detective, with his right hand wrapped in gauze.

Their eyes lit up.

Wu Jun first signalled to two detectives standing nearby; after they stepped out of the yard and walked forward a few steps, Wu Jun casually asked the man, “How did you get injured?”

The man’s voice was hoarse as he replied, “I struggled with the criminal and got hurt.”

“This is the husband of the victim, he just got bandaged up at a relative’s house next door,” said the detective who brought him, sensing the situation and grabbing the man’s injured arm to show everyone as he spoke, “It’s not too serious, just some bleeding.”

Wu Jun nodded, then inquired, “Where did you struggle with them?”

“Just… there…” the man pointed, right near the flowerbed.

“And how did you get injured?”

“The other party picked up a firewood chopper to slash at me, and I blocked it.”

“Where did you block it?”

“Just over there,” the man pointed again to the area of the flowerbed.

Wu Jun and Jiang Yuan both smiled, thinking, No cast-off blood stains, and you dare claim you blocked a knife?