"That's right, it's the sofa bed that Zhang Lan often sleeps on, I remember that I've been here all the time, why is it suddenly gone?" He Lu actually wanted to say it for a long time.

If Gu Chen hadn't reminded him to pay attention to the little changes in the room, he might have almost forgotten.

Zhu Lei was stunned, and then hurriedly said: "That sofa bed, it looks very old, I ...... I'll sell it. ”

"Sold?" Gu Chen asked.

"Yes, sell...... Is there a problem with the sale?" Zhu Lei said.

Gu Chen frowned, and it was difficult to say anything for the time being.

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

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

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

"Is that toolbox with fluorescent agent, right?" Because the toolbox was equipped by Gu Chen after he was promoted to the head of the third criminal investigation team.

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

Gu Chen nodded slightly: "That's right, in fact, what I need is a fluorescent agent." ”

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

In the whole room, everyone was suddenly stunned, they didn't know what Gu Chen was going to do, and the atmosphere was extremely weird.

He Lijuan hesitated again and again, but still plucked up the courage to ask Gu Chen: "Officer Gu, the fluorescent agent you just talked about, this is ...... What is this thing for?"

"Fluorescents are used to test for blood stains. Gu Chen turned to look at her, especially at Zhu Lei, and continued: "Therefore, if criminals want to cover up their crimes by wiping bloodstains, they will end up empty, don't underestimate the current investigation methods." ”

"Officer Gu, are you ...... What are you looking at me for?" Zhu Lei panicked, and he didn't dare to look directly into Gu Chen's eyes.

"I'm reminding someone. Gu Chen said.

In Gu Chen's opinion, Zhu Lei's situation is indeed abnormal.

If Zhang Lan and Zhu Lei have broken up, or are having a conflict, how could she hand over her bank card to Zhu Lei and take the cash in it at will?

Besides, as a student, Zhang Lan's cash in her bank card is her living expenses.

In the two days since Zhang Lan disappeared, Zhu Lei was frantically withdrawing money.

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

It didn't take long for Yuan Shasha to come to Gu Chen with a small toolbox.

"Senior Brother Gu, give. ”

"Fluorescent agent for me. Gu Chen stretched out his hand and said.

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

When everyone saw this, they all followed.

At the top of the stairs, He Lu asked curiously, "Officer Gu, is this thing really so powerful?"

"Then is there a fake?" Gu Chen stood in the center of the room, and also reminded everyone: "You just stay at the staircase, don't come down." ”

"Okay, we're not coming down. He Lu nodded slightly, but continued to ask: "However, how does this fluorescent agent detect blood stains? ”

"You are not studying forensics. Lu Weiwei on the side said with a light smile.

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 floor tiles that have been smeared with blood, you can see the blue fluorescence." ”

"If you spray a fluorescent solution on a floor tile that has no blood stains, it is not fluorescent. ”

"What is the principle of this?" Nursing student Lu Min was also curious, after all, these things were difficult for him to come into contact with in the nursing school.

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

"It's very simple, anyone who has studied chemistry should know it. Gu Chen looked around left and right, also looking for a suitable range.

He glanced back at Lu Min, and then said, "Because the luminol in the fluorescent agent solution reacts with the heme in the blood, a blue light will appear." ”

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

"Even if a drop of blood drops in a large basin of water, you can see fluorescence when you spray it. ”

"Moreover, even if the old blood stains are sprayed on it, you can see the fluorescence. Officer Wang, who was standing behind everyone, also hurriedly added.

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

"That'...... Let's get started. Zhang Lan's father was eager to find his daughter, and he also hurriedly urged.

At this moment, Gu Chen's gaze crossed Zhu Lei, and Zhu Lei obviously had an inadvertent dodge action.

Gu Chen didn't think much about it, picked up the fluorescent agent, and began to spray it all over the house.

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

At this moment, everyone couldn't help but be shocked and couldn't help but scream.

When Gu Chen turned off the light, the walls of the basement actually emitted fluorescence.

Everyone stood at the top of the stairs and watched from side to side......

These fluorescences are not only present on the walls of the basement, but even in the previous position of the sofa bed, leaving a clear outline of the sofa bed when it was lowered.

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

At this moment, Gu Chen looked up at Zhu Lei fiercely and asked, "Zhu Lei, what's the situation?"

"This ...... I don't know that, do I?"

"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 flashes of blue light were actually bloodstained reactions.

Zhu Lei pushed Zhang Lan's father away, and the whole person 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 bright flashlight, shone it on the outline of the sofa bed, and continued:

"These blood stains were obviously produced before the sofa bed was moved, and then the sofa bed was moved away to form this obvious outline. ”

"This shows that there has been blood splattered here before. Lu Weiwei said.

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

Looking up at Zhu Lei, Gu Chen shone a strong flashlight, 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 became the target of public criticism for a while, and directly retorted: "When I sold the sofa that day, I didn't find any blood stains at all. ”

"Where is my daughter?" When He Lijuan heard this, she also wanted to pinch Zhu Lei.

The two almost got into a fight.

"Stop. Gu Chen roared, quickly suppressing the noise between the two.

In turn, he took a cotton swab from the No. 2 toolbox, and took some liquid material from the fluorescent place.

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

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

It didn't take long for the source of the test to react.

According to the content of the forensic manual, Gu Chen was already very sure, which was enough to prove that these liquids were another obvious mark 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 are caused by blood, and these evidences are consistent. ”

"If the sofa bed is being opened at the time and a person sitting on it is attacked, then this pattern of blood splattering is created. ”

"And when the sofa bed was blocking some parts of the walls and floor, when the sofa bed was removed, those parts were clean, and all the rest of the surroundings fluoresced. ”

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

When Zhang Lan's father heard this, his legs were also weak, and he almost fainted on the ground.

"Lao Zhang, Lao Zhang, what's wrong with you? Don't you have an accident?" He Lijuan dragged Zhang Lan's father and woke him up with a sad face.

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

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

At this moment, Lu Min was also panicked, and hurriedly asked Gu Chen: "Officer Gu, did Zhang Lan really encounter an accident?"

"That's for him. Gu Chen glanced at Zhu Lei.

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

"Framing you? This house should be the only one you and Zhang Lan live in, right? Are there other people?" asked Lu Weiwei.

Zhu Lei was speechless for a moment, and he was powerless to refute for a while.

Officer Wang also asked: "I said Zhu Lei, I think you still recruited it, where is Zhang Lan now? Why did you take Zhang Lan's bank card and squander it with Zhang Lan's bank card as soon as she disappeared? You must explain these things clearly today." ”

"Yes, was Zhang Lan killed by you?" He Lu was red-eyed, and he was about to cry at the moment.

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

Whether it is Lu Weiwei, Officer Wang, or Zhang Lan's classmates and roommates Lu Min and He Lu.

When everyone asked, Zhu Lei began to remain silent.

Seeing this, Gu Chen also said bluntly: "Zhu Lei, even if you don't say it, do you think I won't be able to find it? Don't think too smart about yourself." ”

"But officer, I didn't kill anyone, why should I admit it?" Zhu Lei simply broke the jar and broke it, with a posture of fighting Gu Chen to the end.

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

Turning his head 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 fluorescence reactions on the sewer pipe of the bathtub and the stool in the bathroom.

When Gu Chen further examined this wooden stool, he found that it was an old wooden stool.

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

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

At this moment, in the dimly lit bathroom, Gu Chen found that there were many glowing places around the stool.

Gu Chen turned the stool upside down, and it could be clearly seen that the back of the stool had the most fluorescence, indicating that there was also the most blood stains left on it, and there were some tissue objects among them.

And all this is generally something that ordinary people can't see.

"This bathroom looks very clean, which shows that this guy has done a thorough cleaning job. Gu Chen couldn't help frowning.

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

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

Gu Chen gently unscrewed the lid of the sewer pipe, and under the illumination of the strong flashlight, he used his specialty-level observation power to find that there were more tissue fragments stuck inside.

Unlike the small pieces of tissue that were just found on the wooden bench, the lid of the water pipe had quite a large piece of tissue sticking to it.

Of course, for Gu Chen, as long as the fragment was larger than a small patch, it was a fairly large fragment.

But the fragment that Gu Chen found was the size of a little fingertip, and seeing this scene, Gu Chen couldn't help but shudder in his heart.

"So...... Is it a piece of human tissue stuck to the wall of the sewer?"

Gasping, Gu Chen looked back at the living room, and couldn't help but have doubts in his heart.

At this time, Officer Wang had already controlled Zhu Lei, and Lu Weiwei came to Gu Chen's side and asked softly, "Senior Brother Gu, do you have any new discoveries in the bathroom?"

"There was a lot of fluorescence in the bathroom, indicating that someone had washed the blood here, and there might be some tiny human tissue left on the wooden bench. ”

"People...... Human tissue?really?" was also taken aback by Gu Chen's words, and Lu Weiwei's whole body was stunned.

Gu Chen nodded silently, and said, "And I suspect that the murderer moved that stool in the process of committing the murder." ”

He didn't expect to transfer some of the evidence to the inside of the stool when he grabbed it. ”

"And the tissue fragments in the sewer pipes, which were not washed down the sewer pipes due to their different volumes, stuck firmly to the sewer walls. ”

"If we combine everything we find here and give the technical labs enough samples to do DNA testing. ”

"I think the test results should be what I imagined, and this is probably Zhang Lan's DNA. ”

"Yes. Lu Weiwei is also very sure: "We can extract DNA from these tissues, and then compare the DNA with Zhang Lan's father, 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 directly.

Lu Weiwei carefully put the wooden stool away, took out a large transparent forensic 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 Officer Wang, who had been looking at Zhu Lei, he hurriedly asked, "How is it?"

"There was a lot of blood left in the restroom, and we found what appeared to be human tissue on the inside of the wooden bench in the restroom, as well as on the wall of the sewer pipe. ”

"People...... Human tissue?"

As soon as they heard this professional term, Lu Min and He Lu couldn't help but glance at each other.

The two quickly understood what Gu Chen meant, and the two of them were stunned at the moment, and they hugged each other.

"How...... How can this be? how can there be so much blood? how can there be human tissue?"

"Could it be, could it be that Zhang Lan ...... Is she really dead?"

"Oh my God, how can this be?"

Gu Chen walked in front of Zhu Lei, grabbed Zhu Lei's collar, and asked coldly, "Who did you sell that sofa chair to?"

"That's it...... It's just a rag. Hearing what Gu Chen said just now, Zhu Lei also panicked at this moment.

Facing Gu Chen's sharp eyes, he even had weak legs, and his gaze kept dodging.

"Lu Min, He Lu, the two of you 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.

"Good...... Good. The two of them were also panicked at the moment, and they didn't dare to stay in this dry underground layer for a long time.

When Gu Chen's voice fell, he also hurried to the garden on the first floor and went to find Yuan Shasha.

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

Soon, Lu Weiwei seemed to have made a new discovery, and she beckoned to Gu Chen: "Senior Brother Gu, come here, 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, the appearance is very beautiful, Gu Chen found it very clean, but judging from the color of the blade, it seems to have been baked.

Gu Chen didn't say a word, and sprayed the remaining fluorescent agent on the blade, looking forward to showing it all.

However, to Gu Chen's surprise, the fluorescent agent didn't seem to play much role on the blade.

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

"Judging by the blade, it's obviously used, you see this, the blade is notched. Lu Weiwei pointed to a gap.

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 fluorescent agent 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 a little bit on the blade, if he could extract blood DNA, many problems could be solved.

......