The most feared thing in a murder case is the lack of clues.

As long as there are clues, manpower is not lacking.

Just like some people who commit mass murders and then flee to the mountains, the local area can organize a search team of thousands of people in minutes.

Many major case investigation teams organize large-scale investigations, sometimes just to make use of their manpower resources as much as possible. Regardless of whether it is sufficient or necessary, at least the members of the investigation team have something to do.

Having nothing to do can greatly impact the morale of the investigation team.

After Jiang Yuan submitted the clues, the 724 Qinghe Homicide Case Investigation Team immediately sent people to start the investigation work overnight.

At the age of 18, when he was in his third year of high school or freshman year of college, learning ballet proved that the deceased came from a good family background, so it is very likely that the deceased was a student.

Pulling out the list of missing students from Qinghe and several surrounding cities, plus the attribute of learning ballet, even if it goes back several years, the list is only one person.

Zhang Xiaoyun.

A resident of Jianjiang City and a student at Jianjiang No.1 Middle School.

Jianjiang City is adjacent to Qinghe City, and the economic level is not much different from Qinghe City. There is only one training institution in the city that teaches ballet, making it very convenient to find.

However, after the DNA comparison, the members of the investigation team were still somewhat apprehensive.

Purely because the condition of ballet is too narrow, they can easily expand the search range to neighboring cities... and this once again proves one thing:

The murderer is not killing locally.

This is very inconsistent with the modern trend.

Nowadays, the business atmosphere and cultural atmosphere emphasize localization and the formation of circles.

Even blind dates now require having a car and a house, and they even include the first six digits of the ID card number.

To actually not look at the ID card number when committing murder...

Of course, it is easy to understand that the murderer is a bit rebellious.

But the members of the investigation team had to start reflecting on themselves:

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If the murderer doesn't care about localizing the killings, then how large is his scope?

This is not a joke.

The psychology of a murderer will change according to the environment.

Some murderers become unrestrained and violent when they are away from home, but when they return home, they can still be obedient, eat and drink, get beaten by their wives, and get angry at their superiors, without any change.

Some murderers specialize in killing in one place, and this is the mainstream. Especially those who like dismemberment, most of them do it in their own homes.

Reality often responds to this choice in a strange way.

A typical case is Jia Wenge from Nehe City. He and his team members killed 42 people locally, did it for more than three years, and attracted the attention of the investigation team, but nothing happened.

To avoid trouble, they fled to Hangzhou and only did a few "Xianren Jump" (a type of scam), and didn't dare to kill anyone. They were arrested, and three months later, they were executed by firing squad.

The murderer in the 724 case, theoretically familiar with the reservoir and often discards bodies there, should also be a local.

But the only two sources of corpses are not local.

The first deceased, No. 1, came from Wanxiang City in the westernmost part of Shannan Province. It is very likely that he came to Qinghe City on a business trip and died in Qinghe City. But it is also possible that he died outside Qinghe City, such as Jianjiang City.

Now, the fifth deceased is directly a student from Jianjiang City, with limited mobility, so it is very likely that he died in Jianjiang City.

So, does the murderer live in Jianjiang City, which is adjacent to Qinghe City?

It is not uncommon for bodies to be abandoned in a neighboring city, which increases the difficulty of solving the case. Even ancient bandits knew to choose the border areas of three provinces.

For the investigation team, the difficulty seems to have really increased.

In the conference room of Qinghe City Bureau, there were various arguments for two consecutive days.

Fortunately, Jiang Yuan didn't have to attend the meetings anymore.

He stayed in the autopsy room, studying bones every day.

These bodies have been soaked in water for a long time, and most of the flesh has rotted away. The exposed bones have been soaked in a large amount of corpse water, and the color and texture of the bones have changed to varying degrees.

This kind of change is not a problem for some basic judgments.

Just like determining gender, the pelvis is the most useful, but it is not indispensable. The hip bones are equally good, and the skull is also fine. The mandible, sternum, and femur can all be used.

Based on this, even if the bones have been soaked for a long time and eaten by some microorganisms, it does not have much impact.

But if you want to further determine the source of the body, it is obviously more difficult.

The remaining bodies, No. 2, 3, 4, and 6, each have their own complexities.

There are four autopsy tables in the autopsy room, and four sets of bones are displayed.

Wang Lan assigned each forensic doctor a body, except for Jiang Yuan.

The first two bodies relied on Jiang Yuan's judgment, so his knowledge of forensic anthropology is obviously sufficient for the job. It may even surpass everyone else.

Wang Lan can't help much except for giving him full trust.

The first day, Jiang Yuan toured in front of the four sets of bones.

Afterwards, Jiang Yuan focused more and more on the bones of No. 3.

The No. 3 bones were the ones that had been hacked with an axe.

The wear and tear on the lumbar vertebrae and leg bones of this set of bones were severe, and Jiang Yuan's initial judgment was that the person had engaged in physical labor.

Of course, this judgment is not a problem, but the range is too large, and it is basically impossible to find the person based on this.

Initially, Jiang Yuan was planning to study the traces of the axe.

If the type of axe could be determined, even if the case couldn't be solved, it could provide some clues. For example, the common fire axe or the small axe used for chopping firewood, etc., there are definitely not many buyers.As it turned out, Jiang Yuan had underestimated the tool mark examination. With his level of expertise in this area, he couldn't trace the origin of the axe at all.

Determining the time of death... this path was even more impossible.

The underwater world was a closed one. For a body that had been submerged for so long, determining the time of death usually required external help. For example, observing how many generations of maggots had reproduced, how long the algae had grown...

Not to mention the lack of conditions, even if they were met, the estimation of the time of death could only be made in years.

In fact, determining the time of death was the most difficult and profound part of forensic science, or in other words, the least accurate part.

In fresh cases, where the body was still warm, the liver and rectal temperatures could be measured. But in old cases like this one, where the liver and rectum were gone, and it was unknown whether the microbes had regenerated...

In the end, what Jiang Yuan could study was the most basic trace on the bones.

Theoretically, a skeleton could provide many traces of a person's life before death, not only about their lifestyle, but also about their work, diseases, or environment.

A suitable example for modern people would be, if 20 people were killed in a subway and their flesh was cooked off, leaving only the bones, what would be the most common trace on the skeleton?

The incidence of excessive wear on the cervical vertebrae would definitely be extremely high.

Jiang Yuan had already seen the wear on the lumbar vertebrae and leg bones of the third body. Upon further observation, he finally concluded that the wear on his knees, tibia, and even heels should have come from daily life or work.

However, he was unsure what kind of job would cause wear in these areas.

He thought about it for the time it took to cook a bowl of instant noodles, but couldn't figure it out, so he directly called Liu Jinghui.

In Jiang Yuan's view, Liu Jinghui, who was good at reasoning, could probably be of some use at times like this.

Upon receiving the call, Liu Jinghui, a fourth-level senior police officer from Shannan Provincial Department, rushed to the autopsy room.

Jiang Yuan found him a protective suit and said, "You didn't really need to come over. We could have just talked over the phone."

Liu Jinghui shook his head, "There are many things that need to be seen in person to be clear."

"Alright then." Jiang Yuan led him to the third autopsy table and handed him a tibia, saying, "Take a look for yourself."

The tibia is the larger bone on the inner side of the lower leg.

It was very hard and could be held in one hand. Clever ancient people had discovered the properties of the tibia long ago, so thousands of years ago, they had ground tibias into daggers, even carving blood grooves into them.

Judging from the shape of unearthed artifacts, the tibia was an excellent material for daggers.

However, as pure evidence, Liu Jinghui looked at it back and forth for a long time and couldn't see anything.

"Explain it to me." Liu Jinghui sighed.

Several forensic doctors also quietly gathered around, wanting to hear Jiang Yuan's explanation.

"The wear is mainly here. The bone has become rough." Jiang Yuan held the tibia, showing the selected side to Liu Jinghui.

Liu Jinghui still couldn't see it.

"That's why I said we could have just talked over the phone." Jiang Yuan said.

"It's not far anyway." Liu Jinghui argued, then turned his attention back to the body, asking, "What kind of movement caused this wear?"

"Perhaps frequent squatting or something like that." Jiang Yuan demonstrated.

Liu Jinghui looked closely and nodded slightly, "Knee, tibia, heel."

Jiang Yuan nodded, "It's a pity it's a male. If it were a female, it might have been someone in the service industry."

"Wow..." Liu Jinghui clicked his tongue, looking at Jiang Yuan, "You're quite knowledgeable. As expected of someone from Jiang Village, so young and..."

"I'm referring to service staff, like shoe salespeople or flight attendants in first class."

"Men can also do these jobs, right? Why are you so fixated on gender?" Liu Jinghui joked.

Jiang Yuan curled his lips, "Heavy physical labor."

"First-class flight attendants who often carry luggage. Or shoe salespeople who work part-time at express delivery points at night?"

"I was just giving examples." Jiang Yuan shook his head, "Considering the victim's age, the time he spent squatting daily would be much longer than that of a shoe salesman."

"A welder?"

Jiang Yuan hesitated for a moment, then nodded, "Possible."

"An athlete of some sport, like skiing?"

"Also possible."

Liu Jinghui guessed a few more occupations, and roughly understood Jiang Yuan's judgment.

"This murderer kills very casually." Liu Jinghui sighed.

Jiang Yuan hummed in agreement, put the tibia back in place, looked at the other bodies, and asked Liu Jinghui, "How's the special investigation team doing?"

"It's a mess." Liu Jinghui said in a low voice.

"Didn't the provincial department send you to provide strategic guidance?" Jiang Yuan looked at Liu Jinghui.

"My judgment is that this person is likely committing random acts." Liu Jinghui also looked at Jiang Yuan, "Do you know how to solve such cases?"

Jiang Yuan shook his head. There was a reason why random acts accounted for more than half of the unsolved murder cases in each province.

"We need to pile up known conditions. To find order in disorder, listing known conditions is the most basic step." Liu Jinghui said, "I've called in two more teams of frogmen to see if there are any more bodies in the reservoir. If we can't find any, the bodies we have now are all we know."