1995, Starting as a Criminal Investigation Expert

The next day, at the trace evidence laboratory on the fifth floor of the Second Research Institute.

In the operating room, Li Shuzheng was using a measuring cup to prepare EOS solution.

Wang Ze'an and Tan Ligang, the director of the trace evidence laboratory, were also there, watching silently.

There were also quite a few people guarding outside the door.

Liu Yaoqing was there, talking to Yang Shaoting, the deputy director of the Criminal Investigation Department of the Municipal Public Security Bureau.

Anjing is the capital city, and its level is high, similar to a provincial department. The municipal bureau has a criminal investigation department.

In prefecture-level cities like Nanjiang, Xu Qiang, as the branch captain, often takes the lead in handling cases.

In a metropolis like Anjing, the head of the criminal investigation department is a very high-ranking official, mainly responsible for overseeing the overall situation. The highest rank for handling specific cases is usually the deputy head.

As for the ministry, its role is mainly to provide guidance and supervision in handling cases.

Therefore, Yang Shaoting was solely responsible for investigating this series of home invasion robberies.

As the two were talking, a middle-aged man arrived with his entourage.

His hair was completely black, but he had quite a few wrinkles on his face, indicating that he was not young, and his hair was dyed.

"Old Liu, Shaoting."

He greeted them with a smile, glanced at the laboratory, and then his gaze fell on Li Shu.

I've heard about it; he's very young.

But I didn't expect him to be so young.

"Director Liu, why did you come in person?" Yang Shaoting asked.

The man in front of me is Liu Xinfeng, the deputy director of the Fifth Criminal Investigation Bureau of the Ministry.

With the five bureaus coordinating more work, there are now four deputy bureau chiefs, each responsible for a specific area.

Liu Xinfeng was in charge of major and important cases.

Liu Xinfeng stood with his hands behind his back and said, "That's true. There might be progress in the case, so I have to make time to come over."

The case had been a mess for him for the past two years, and he was really holding back his anger.

Yang Shaoting glanced around the room and said, "The key is, we don't even know if it will work."

Liu Xinfeng glanced at him and said, "What, you think he's too young?"

Yang Shaoting quickly shook his head, saying that he didn't mean it that way.

Liu Xinfeng watched quietly and said, "What does ability have to do with age? Last year, Cao Yanqi's theft case, how was it finally solved? I remember you all thought he was young, but what happened?"

Last summer, a master thief appeared in the Ankyo area.

The wall is only two or three meters high; you can climb it with a single step, just like in martial arts novels, where scaling walls and leaping across rooftops is a piece of cake.

In just a few months, he committed 29 crimes, stealing nearly a million yuan worth of property.

This person appeared and disappeared without a trace, causing Yang Shaoting and his men a lot of trouble.

There was no other way, so Director Zhao of the Fifth Bureau thought of someone. In 92, at the National Youth Skills Competition, a young policeman from Songpu performed an incredible feat of creating composite sketches, which was unbelievable.

So they invited this person over from Matsuura.

It was quite a blunder at the time. The detective who was sent to pick him up thought that since he was an expert, he should at least be an old man in his fifties or sixties with white hair.

Who knew it was a young man in his early thirties?

At first, Yang Shaoting thought the young man was too young and didn't dare to use him, so he left him hanging for two days.

As a result, this young railway police officer named Zhang Xin drew a composite sketch of the suspect on the same day.

He finished the painting that day and went back to Matsuura on his own the next day.

As soon as the person got off the train, the suspect was already apprehended here.

The police officers who were staking out the location recognized the suspect at a glance from the sketch, saying that the drawing was almost identical to the real person, which was incredibly amazing.

Upon hearing this, Yang Shaoting gave an awkward smile and said, "Zhang Xin is truly capable, but I wonder if Li Shu has the same ability."

Zhang Xin is at least 35 years old and has been working for many years, while Li Shu is only 21, having just graduated from police academy. There's a whole generation difference in age.

Inside the room, Li Shu had already prepared the EOS solution.

He didn't hold anything back; he told Wang Ze'an everything about the configuration process and proportions.

"Let's try it out first."

Although the research institute assured him that he was fully in charge and that they had complete confidence in him, Li Shu still wanted to conduct an experiment to show everyone.

Whether something works or not isn't determined by what you say.

Bicycle handlebar grips made of the same material and with the same pattern.

Wang Ze'an pricked his finger first, smeared the smear all over his right hand fingers, and only wiped it off on his body after the bleeding stopped. Then he gripped the handlebars in a normal grip position.

The sample production is complete.

Without hesitation, Li Shu sprayed on the EOS solution, immediately went next door, turned off the lights and closed the windows, and used the institute's multi-band light source to illuminate the room.

In the darkness, by matching the wavy shape below the handle to the position of the fingers, an orange-red fluorescence was indeed displayed.

Tan Ligang and others present immediately began to whisper among themselves.

I already knew the principles of dyeing, but seeing it in person still amazed me.

"Shall we begin?" Li Shu asked.

This bicycle is perfectly preserved in the research institute.

Before even removing the condom, Li Shu sprayed the solution, spraying it on both sides.

The dyeing process was quick. Li Shuchong and Wang Zean nodded, signaling to turn off the lights.

After the light is turned off, shine it on the left side first.

Sure enough, there wasn't.

Just as Wang Ze'an and his team had predicted, the suspect's left hand was not stained with blood.

That leaves only the right side.

Li Shu took a deep breath, aimed the light source at the right handle, and thought, "Whether it works or not depends on this."

In the darkness, on the inside of the cover, near the top bottom, an orange-red fluorescent reaction appeared as the light swept across it.

In an instant, the oppressive atmosphere in the room eased.

Wang Ze'an was extremely excited and exclaimed, "I told you, there is, there definitely is!"

Everyone was excited.

This case is so heinous, yet it has remained unsolved for over two years.

It's fair to say that everyone who came into contact with this case felt a heavy weight on their mind, constantly thinking about it.

Now that we've finally made a breakthrough, how can we not be excited?

However, amidst his excitement, Tan Ligang's gaze sharpened, and he frowned, saying, "These fingerprints are a bit blurry."

Li Shu has already noticed this.

First of all, the cover must be rough and textured, and the fluorescence will show a slight diffuse reflection, which will make it appear blurry to the naked eye at first glance.

This is a minor issue that can be addressed later.

The big problem was that Li Shu noticed that the fingerprints had obvious scratches and were overlapping.

You can tell from the edge outline that the shape is wrong.

Li Shu squatted down, leaned closer to take a closer look, and gritted his teeth, saying, "I think it's because the suspect's fingers weren't consistently gripping the same spot during his escape."

"For example, if he squeezes the brake, there is a process of letting go and then gripping again, which causes the fingerprints to overlap in some areas and slide."

Normally, when a suspect is fleeing in a hurry and riding fast, they should be holding on to the handlebars tightly.

But you always have to squeeze the brake, right? Squeeze it and then squeeze it back. Even if there's a wavy structure under the cover to match your finger, it's still a fingerprint. Even a movement at the micrometer level will cause the fingerprint to become blurry.

"That's right."

Tan Ligang nodded in agreement with Li Shu's idea and said, "Look at that."

He squatted down and pointed to the handle, saying, "It's quite obvious. The little finger and the ring finger are clearer because these two fingers bear less force. And even when you're applying the brakes, it's usually the index and middle fingers that exert force."

That's what they say, but even the little finger can sometimes overlap.

He pursed his lips and said, "Li Shu, I've read your articles. You can analyze and infer from blurred and overlapping fingerprints, and then use topological theory to compare them. Do you think we have the conditions to do that now?"

Everyone turned to look at Li Shu.

These people would be considered experts anywhere in the country.

But blurry fingerprints are a headache for anyone.

Li Shu wanted to say this, so he said, "I will try my best. I also think we can't just focus on the grip. We might be able to extract fingerprints from other places, like the brakes."

Li Shu pointed to the two brake levers below the handlebars.