I am a super cop

Chapter 707 Fluorescent Agent 【Seeking Monthly Ticket】

"That's right, it's the sofa bed that Zhang Lan used to sleep on. I remember it was here all the time, why is it gone all of a sudden?" He Lu actually wanted to talk about it a long time ago.

If Gu Chen hadn't reminded himself to pay attention to every change in the room, he might have almost forgotten it.

Zhu Lei was stunned for a moment, and then hurriedly said: "Just that sofa bed, it looks quite old, I... I'll sell it."

"Sold?" Gu Chen asked.

"Yes, it's sold...it's sold, is there a problem?" Zhu Lei said.

Gu Chen frowned, unable to say anything for now.

After all, selling furniture seems to be the freedom of the residents, but Gu Chen still has some scruples about Zhang Lan's connection.

After all, Zhang Lan's disappearance, any item related to Zhang Lan seems to provide Gu Chen with a source of investigation.

Looking at the dark basement, Gu Chen hesitated for a moment, then turned to Yuan Shasha and said, "Xiao Yuan, go to the trunk of the car and get my No. 2 toolbox."

"It's the toolbox with fluorescent agent, right?" Because the toolbox was equipped by Gu Chen after he was promoted to the leader of the third criminal investigation team.

Gu Chen got a lot of good things from forensic assistant Gao Chuanfeng, so Yuan Shasha didn't know very well, so she asked him.

Gu Chen nodded slightly: "That's right, actually what I need is fluorescent agent."

"Okay, I'll get it now." Yuan Shasha nodded silently, and left the scene immediately.

In the whole room, everyone was startled suddenly, they didn't know what Gu Chen was going to do, and the atmosphere seemed very strange.

He Lijuan hesitated again and again, but she mustered up the courage to ask Gu Chen: "Officer Gu, the fluorescent agent you mentioned just now, this... what is this thing? What is it used for?"

"Fluorescent agents are used to test bloodstains." Gu Chen turned to look at her, especially at Zhu Lei, and continued: "So, if criminals want to cover up their crimes by wiping bloodstains, they will eventually Don’t underestimate the current investigation methods.”

"Officer Gu, you... what are you looking at me for?" Zhu Lei panicked and didn't dare to look Gu Chen in the eyes.

"I'm reminding someone." Gu Chen said.

From Gu Chen's point of view, Zhu Lei's situation is indeed abnormal.

If Zhang Lan and Zhu Lei had already broken up, or were having conflicts, why would she hand over her bank card to Zhu Lei, and take the cash in it at will?
Besides, as Zhang Lan is a student, the cash in the bank card is her living expenses.

But during the two days when Zhang Lan disappeared, Zhu Lei was withdrawing money frantically.

Without too much speculation, Gu Chen can guess where the money was spent.

Not long after, Yuan Shasha came to Gu Chen with a small toolbox.

"Brother Gu, here it is."

"Give me the fluorescent agent." Gu Chen stretched out his hand and said.

After taking the fluorescent agent from Yuan Shasha, Gu Chen came to the basement again.

Seeing this, everyone followed.

At the stairs, He Lu asked curiously, "Officer Gu, is this thing so powerful? Can it really detect blood?"

"Is there still a fake?" Gu Chen stood in the middle of the room, and reminded everyone: "You stay at the stairs, don't come down."

"Okay, we won't come down." He Lu nodded slightly, but continued to ask: "But, how does this fluorescent agent detect blood? We don't seem to have learned about this in nursing."

"You don't study forensic medicine." Lu Weiwei said with a smile on the side.

Gu Chen also smiled and said: "Don't underestimate this fluorescent agent. Even if the blood stains on the floor tiles are wiped clean, as long as you spray the fluorescent agent solution on the blood-stained floor tiles, you can see blue fluorescence."

"If you spray the fluorescent agent solution on the floor tiles without blood stains, there will be no fluorescent reaction."

"What's the principle?" Lu Min, a nursing student, was also very curious. After all, it was very difficult for me to come across these things in the nursing school.

Meeting Gu Chen today was a bit of an eye-opener.

"It's very simple. Those who have studied chemistry should know it." Gu Chen looked around, also looking for a suitable range.

He turned his head and glanced at Lu Min, and then said again: "Because the luminol in the fluorescent agent solution reacts with the hemoglobin in the blood, a blue light will appear."

"And this luminol solution is now widely used in criminal investigation methods, and its verification effect is very sensitive."

"Even if a drop of blood is dropped in a large basin of water, you can still see the fluorescence after spraying it."

"Besides, even if you spray it with old blood, you can still see the fluorescence." Officer Wang, who was standing behind everyone, quickly added.

"Yes, that's the truth." Gu Chen said.

"Then... let's start quickly." Zhang Lan's father was eager to find a daughter, and hurriedly urged.

At this moment, Gu Chen glanced past Zhu Lei, and Zhu Lei obviously made an inadvertent dodge.

Without thinking too much, Gu Chen picked up the fluorescent agent and started spraying it in every corner of the house.

After some operations, Gu Chen slowly walked to the light switch in the house and turned off the light.

At this moment, everyone couldn't help but startled and screamed involuntarily.

When Gu Chen turned off the lights, the walls of the basement actually glowed with fluorescence.

Everyone stands at the stairs and observes...

These fluorescences are not only present on the walls of the basement, but even where the sofa bed was placed before, leaving a clear outline of the sofa bed when it is lowered.

What was even more astonishing was that Gu Chen also saw other fluorescent plaques, which continued to the bathroom in the basement, and some even continued to the stairs.

At this moment, Gu Chen suddenly looked up at Zhu Lei, and asked, "Zhu Lei, what's going on?"

"This...I don't know about this either?"

"Did you do something to my daughter?" Because of Gu Chen's explanation of the fluorescent agent just now, Zhang Lan's father quickly realized that all these flashing blue lights were actually the reaction of blood stains.

Zhu Lei pushed Zhang Lan's father away, and said in panic, "You...don't talk nonsense, I...how do I know what's going on in this room."

"I don't know what's going on, so why are you selling the sofa bed?"

In the dimly lit room, Gu Chen turned on the strong flashlight, pointed at the outline of the sofa bed, and continued:

"These bloodstains were obviously produced before the sofa bed was removed, and the obvious outline was formed after the sofa bed was removed."

"This shows that blood was spattered here before." Lu Weiwei said.

"That's right." Gu Chen nodded and continued: "Not only on the sofa bed, but also on the walls, on the stairs, and the distance between the bathroom and the living room, there are blood stains."

Looking up at Zhu Lei, Gu Chen shone a strong flashlight on it, and Zhu Lei immediately covered it with his hands.

"Zhu Lei, what happened in the basement? Where is Zhang Lan?"

"I...I don't know, besides, you said that this fluorescent agent can detect blood stains, I...how do I know if this is true?"

Zhu Lei immediately became the target of public criticism, and directly retorted: "When I sold the sofa that day, I didn't find any blood at all."

"You still want to deny it? Where is my daughter?" He Lijuan heard that and wanted to pinch Zhu Lei.

The two almost had a fight.

"Stop it all." Gu Chen roared, quickly suppressing the noise of the two of them.

In turn, I took a cotton swab from the No. 2 tool box, and took some liquid substances from the place where the fluorescence was emitted.

Gu Chen used the basement as a chemical testing room. Under the illumination of a strong flashlight, Gu Chen took out a bottle of chemical reagents from the No. 2 toolbox.

Afterwards, Gu Chen sat on the ground, and directly used chemical reagents to conduct a simple test on these liquids in front of everyone.

Not long after, the detection source responded.

According to the contents of the forensic medical manual, Gu Chen was already very sure that this was enough to prove that these liquids were another obvious sign of blood.

"Zhang Lan must have had an accident here." After seeing this, Gu Chen stood up directly and said, "I now have good evidence that all these reactions were caused by blood, and the evidence is consistent. "

"If the sofa bed was opened at the time and a person sitting on it was attacked, then there would be this pattern of blood splatter."

"While the sofa bed was blocking certain areas of the wall and floor, after the day bed was removed, those areas were clean, and everything else around them fluoresced."

"That means Zhang Lan might have been killed in the basement?" Lu Weiwei couldn't believe it.

When Zhang Lan's father heard this, his legs went limp and he almost fainted on the ground.

"Old Zhang, what's the matter with you, Old Zhang? Don't you have any trouble?" He Lijuan grabbed Zhang Lan's father and woke him up with a mournful face.

"Xiao Yuan, help take Mr. Zhang out of the room." Gu Chen said.

"No problem." Yuan Shasha nodded and helped He Lijuan to lift Zhang Lan's father out of the room.

At this moment, Lu Min was also panicked, and hurriedly asked Gu Chen, "Officer Gu, did something happen to Zhang Lan?"

"I'll ask him that." Gu Chen glanced at Zhu Lei.

Zhu Lei took a step back and waved his hands to clarify: "Comrade police, I... I really don't know, don't you want to frame me?"

"Framing you? You and Zhang Lan should be the only ones living here in this house, right? Are there other people?" Lu Weiwei asked.

Zhu Lei was speechless for a moment, unable to refute for a while.

Police officer Wang also asked: "I said Zhu Lei, I think you should recruit. Where is Zhang Lan now? Why did you use Zhang Lan's bank card to withdraw money and squander it as soon as Zhang Lan disappeared? What are you doing today? It must be made clear."

"Yes, did you kill Zhang Lan?" He Lu's eyes were red, and she was about to cry right now.

However, at this time Zhu Lei kept silent and began to refuse to answer any questions.

Whether it's Lu Weiwei, Police Officer Wang, or Zhang Lan's classmate and roommate Lu Min and He Lu.

Zhu Lei began to remain silent when everyone asked questions.

Seeing this, Gu Chen also said straightforwardly: "Zhu Lei, even if you don't tell me, do you think I can't find it? Don't think too smart of yourself."

"But police officer, I didn't kill anyone, why should I admit it?" Zhu Lei simply broke the jar, as if he was fighting Gu Chen to the end.

Gu Chen nodded slightly, and continued: "I sprayed a lot of fluorescent agent in the room, all of which can tell me what happened in the basement floor at that time."

Turning to look at the bathroom, Gu Chen continued to search.

From the fluorescence in the living room to the bathroom, Gu Chen found that there were many strong fluorescent reactions on the drain pipe of the bathtub and the stool in the bathroom.

When Gu Chen further inspected this wooden stool, he found that it was an old wooden stool with a long history.

In Gu Chen's impression, this kind of stool should have existed in his childhood, and there are the most such stools in the community canteen.

Gu Chen put on his white gloves and turned off the strong flashlight.

At this moment, in the dim bathroom, Gu Chen found many glowing places around the stool.

Gu Chen turned the stool over, and he could clearly see that the back of the stool had the most fluorescence, indicating that the most bloodstains remained on it, and there were some tissue objects in it.

And all of these things are generally invisible to ordinary people.

"This bathroom looks very clean, it can be seen that this guy has done a thorough job of cleaning." Gu Chen couldn't help frowning.

But after turning the stool over, Gu Chen still hesitated, feeling that he should take the stool back for testing.

So Gu Chen put the stool aside first, and then began to check the drain pipe of the bathtub.

Gu Chen gently unscrewed the cover of the sewer pipe, and under the illumination of a strong flashlight, using his expert observation ability, he found that there were more tissue fragments stuck inside.

Unlike the small tissue fragments found on the wooden bench just now, quite large tissue fragments were stuck to the cover of the water pipe.

Of course, for Gu Chen, as long as the fragments are larger than a small plaque, they are quite large fragments.

But the fragment that Gu Chen found was as big as the tip of a little finger. Seeing this scene, Gu Chen could not help but shudder in his heart.

"So... it's a piece of human tissue stuck to the wall of the sewer pipe?"

Taking a deep breath, Gu Chen looked back at the living room, feeling puzzled in his heart.

At this time, Police Officer Wang had already controlled Zhu Lei, and Lu Weiwei came to Gu Chen's side and asked softly, "Junior Brother Gu, did you find anything new in the bathroom?"

"There is a lot of fluorescence in the bathroom, which means that someone has cleaned the blood here, and there may be some tiny human tissues left on the wooden stool."

"Human... human body tissue? Is it real or not?" Also startled by Gu Chen's words, Lu Weiwei's eyes froze.

Gu Chen nodded silently, and said again: "And I suspect that the murderer moved the stool during the murder."

"It didn't occur to him that when he grabbed the inner part of the stool, he would transfer some of the evidence to it."

"Furthermore, those tissue fragments in the sewer pipes failed to be washed away along the sewer pipes due to their different volumes, and they were firmly stuck to the walls of the sewer pipes."

"If we put everything together that we've found here and give enough samples to the tech lab to do DNA testing."

"I think the test results should be what I imagined. This is very likely to be Zhang Lan's DNA."

"Yes." Lu Weiwei is also very sure: "We can extract DNA from these tissues, and then compare it with Zhang Lan's father's DNA. If these samples are really consistent with Zhang Lan's father's DNA sample, then We have enough evidence."

"Take that wooden stool back." Gu Chen stood up and walked out of the bathroom.

Lu Weiwei carefully held the wooden stool, took out a large transparent evidence collection bag from the equipment bag, and wrapped the wooden stool in it.

Seeing Gu Chen and Lu Weiwei coming out of the bathroom and looking at Zhu Lei's Police Officer Wang, he hurriedly asked, "How is it?"

"There is a lot of blood in the bathroom, and we found objects suspected of human tissue on the inside of the wooden stool in the bathroom and on the wall of the downpipe."

"Human...human tissue?"

Upon hearing this term, Lu Min and He Lu couldn't help but look at each other.

The two quickly understood what Gu Chen meant, their eyes froze with fright at the moment, and they hugged each other.

"How...how did this happen? How could there be so much blood? How could there still be human tissue?"

"Could it be that Zhang Lan...is she really dead?"

"My God! How could this be?"

Gu Chen walked up to Zhu Lei, grabbed Zhu Lei by the collar, and asked coldly, "Who did you sell that sofa bed to?"

"Just...just a trash collector." Hearing what Gu Chen said just now, Zhu Lei panicked at the moment.

Facing Gu Chen's sharp eyes, his legs even went weak, and he kept avoiding his eyes.

"Lu Min, He Lu, you two go to the garden on the first floor to find my colleague and see if there are any suspicious signs of burial in the garden on the first floor." Gu Chen said.

"Okay...Okay." The two of them were also panicked at this moment, and they didn't dare to stay in this dry basement floor.

When Gu Chen finished speaking, he hurried to the garden on the first floor to find Yuan Shasha.

At this moment, Gu Chen turned on all the lights on the basement floor, and continued to collect strong evidence in every corner of the room.

Soon, Lu Weiwei seemed to have a new discovery. She waved to Gu Chen: "Junior Brother Gu, come quickly, there seems to be a knife under this wooden cabinet."

"Let me see." Gu Chen squatted down, and quickly took the sharp weapon from Lu Weiwei's hand.

This is a machete with a very beautiful appearance. Gu Chen found that it was very clean, but judging from the color of the blade, it seemed to have been baked.

Without saying a word, Gu Chen sprayed the remaining fluorescent agent on the blade, hoping to show it.

However, to Gu Chen's surprise, the fluorescent agent didn't seem to have much effect on the cutting edge.

Gu Chen couldn't help frowning: "Could it be that the things on it have disintegrated?"

"Judging from the edge of the blade, it's obviously used. Look at this, the edge of the blade is notched." Lu Weiwei pointed to a gap and said.

Gu Chen nodded slightly, and said, "That's right, there are signs that there is a small amount of blood on the machete."

"But probably because there was so little blood, the fluorescer didn't seem to react much."

"Then try again with reagents." Officer Wang said.

Gu Chen nodded in agreement, thinking that if he could detect every little bit on the knife's edge, if he could extract blood DNA, many problems could be solved.

……

　The previous single chapter was blocked, please post the easter egg again, it will be visible on the starting point client.

　　
　
(End of this chapter)