"Yes, it's the sofa bed where Zhang Lan often sleeps. I remember it was always here before. Why is it suddenly gone?" He Lu had actually wanted to say it for a long time.
If Gu Chen hadn't reminded him to pay attention to every change in the room, he might have almost forgotten it.
Zhu Lei was stunned, and then quickly said: "It's just that sofa bed. It looks quite old, so I... I'll sell it."
"Sold?" Gu Chen asked.
"Yes, sell it...sell it, is there any problem?" Zhu Lei said.
Gu Chen frowned, unable to say anything for the time being.
After all, selling furniture seems to be the freedom of the residents, but it involves Zhang Lan's contact, and Gu Chen still has some scruples.
After all, Zhang Lan's disappearance and any items related to Zhang Lan seemed to provide Gu Chen with a source of investigation.
Looking at the dark basement, Gu Chen hesitated for a moment, turned around and said to Yuan Shasha: "Xiao Yuan, go to the trunk of the car and get my No. 2 tool box."
"It's the toolbox with the 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 stuff from forensic assistant Gao Chuanfeng, so Yuan Shasha didn't know much about it, so she asked him.
Gu Chen nodded slightly: "Yes, actually what I need is fluorescent agent."
"Okay, I'll get it right away." Yuan Shasha nodded silently and left the scene immediately.
Everyone in the whole room was suddenly startled, not knowing what Gu Chen was up to, and the atmosphere seemed extremely strange.
He Lijuan hesitated again and again, but finally plucked up the courage to ask Gu Chen: "Officer Gu, the fluorescent agent you just mentioned, this... what is it? What is it used for?"
"The fluorescent agent is used to detect blood stains." Gu Chen turned around and looked at her, especially Zhu Lei, and continued: "So, if criminals want to cover up their crimes by wiping blood stains, they will eventually
It's all in vain, so don't underestimate the current investigation methods."
"Officer Gu, you...what are you looking at me for?" Zhu Lei felt panicked and did not 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 was indeed abnormal.
If Zhang Lan and Zhu Lei had broken up or were having a conflict, how could she hand her bank card to Zhu Lei and withdraw 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.
Not long after, Yuan Shasha came to Gu Chen carrying a small toolbox.
"Senior 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 him one after another.
At the top of the stairs, He Lu asked curiously: "Officer Gu, is this thing really so powerful? Can it really detect blood stains?"
"Is there still a lie?" Gu Chen stood in the center of the room and reminded everyone: "Just stay at the stairs and 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 stains? None of us nursing students seem to have learned this aspect."
"You are not studying forensic medicine." Lu Weiwei said with a 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 blood-stained floor tiles, you can see blue fluorescence."
"If you spray a fluorescent agent solution on floor tiles without blood stains, there will be no fluorescent reaction."
"What is the principle of this?" Nursing student Lu Min was also curious. After all, it was difficult for her to come into contact with these things in the nursing school.
Meeting Gu Chen today was a bit eye-opening.
"It's very simple. Anyone who has studied chemistry should know it." Gu Chen looked around, looking for a suitable range.
He turned back to look at Lu Min, and then added: "Because the luminol in the fluorescent agent solution reacts with the heme in the blood, a blue light will appear."
"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 is dropped into a large basin of water, you can still see fluorescence when sprayed on it."
"Moreover, even if old blood is sprayed on it, you can still see the fluorescence." Officer Wang, who was standing behind the crowd, quickly added.
"Yes, that's the truth." Gu Chen said.
"Then... let's start quickly." Zhang Lan's father was eager to find a girl, so he quickly urged her.
At this moment, Gu Chen's eyes passed over Zhu Lei, and Zhu Lei obviously made an inadvertent dodge movement.
Without thinking 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 be startled and screamed involuntarily.
When Gu Chen turned off the lights, the walls of the basement actually glowed with fluorescence.
Everyone stood on the left and right sides of the stairs and observed...
These fluorescent lights are not only present on the walls of the basement, but even where the sofa bed was previously placed, 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 patches that extended all the way to the basement bathroom, and some even extended to the stairs.
At this moment, Gu Chen looked up at Zhu Lei and asked, "Zhu Lei, what's going on?"
"This...I don't know this either?"
"Did you do something to my daughter?" Because of Gu Chen's explanation of fluorescent agents just now, Zhang Lan's father quickly realized that all these flashes of blue light 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 the situation is, so why did you sell the sofa bed?"
In the dim room, Gu Chen turned on the strong flashlight, shined it on the outline of the sofa bed, and continued:
"These bloodstains were obviously produced before the sofa bed was moved, and it was only after the sofa bed was moved that this obvious outline was formed."
"This shows that blood was spilled here before," Lu Weiwei said.
"That's right." Gu Chen nodded and continued: "There are blood stains not only on the sofa bed, but also on the walls, stairs, and the distance between the bathroom and the living room."
Looking up at Zhu Lei, Gu Chen shined a strong flashlight at 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 this fluorescent agent can detect blood stains. How...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 at all."
"You still want to deny it? Where is my daughter?" Hearing this, He Lijuan also wanted to pinch Zhu Lei.
The two almost came to blows.
"Stop it, everyone." Gu Chen shouted and quickly suppressed the noise between the two of them.
Then he took a cotton swab from tool box No. 2 and collected some liquid substance from the fluorescent area.
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 tool box No. 2.
Then Gu Chen sat on the floor and conducted a simple test on these liquids using chemical reagents in front of everyone.
Not long after, the detection source responded.
According to the contents of the forensic 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 are caused by blood, and the evidence is consistent.
"
"If the sofa bed was open and a person sitting on it was attacked, then you would have this pattern of blood splatter."
"Whereas the sofa bed was blocking certain areas of the wall and floor, once the sofa bed was removed, those areas were clear, while everything else around it would fluoresce."
"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 weak and he almost fainted and fell to the ground.
"Old Zhang, what's wrong with you, Old Zhang? Don't let anything happen to you?" He Lijuan grabbed 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 carry Zhang Lan's father out of the room.
At this moment, Lu Min was in panic and quickly asked Gu Chen: "Officer Gu, is Zhang Lan really in trouble?"
"I'll have to ask him now." Gu Chen glanced at Zhu Lei.
Zhu Lei took a step back, waved his hand and clarified: "Comrade police, I... I really don't know, don't you want to frame me?"
"Falsely accusing you? You and Zhang Lan should be the only ones living here in this house, right? Are there others?" Lu Weiwei asked.
Zhu Lei was speechless and unable to refute for a moment.
Officer Wang also asked: "Zhu Lei, I think you should do it. Where is Zhang Lan now? Why did you take Zhang Lan's bank card to withdraw money and squander it today?"
It must be explained clearly.”
"Yes, was Zhang Lan killed by you?" He Lu's eyes were red and she was about to cry at this moment.
However, Zhu Lei kept silent at this time and began to refuse to answer any questions.
Whether it's Lu Weiwei, Officer Wang, or Zhang Lan's classmates and roommates Lu Min and He Lu.
Zhu Lei initially remained silent as everyone asked questions.
When Gu Chen saw this, he said bluntly: "Zhu Lei, even if you don't tell me, do you think I can't find you? Don't think of yourself as too smart."
"But officer, I didn't kill anyone, why should I admit it?" Zhu Lei simply broke the jar and threw it, as if he was fighting with Gu Chen to the end.
Gu Chen nodded slightly and continued: "I sprayed a lot of fluorescent agent in the room. These can tell me what happened on this basement floor at that time."
Turning his head and looking at the bathroom, Gu Chen continued his search.
The fluorescence from the living room continued into the bathroom. Gu Chen found that there were many strong fluorescent reactions in the sewer pipes of the bathtub and on the stools in the bathroom.
When Gu Chen further inspected the wooden bench, he found that it was an old wooden bench.
In Gu Chen's impression, this kind of stool should have existed in his childhood, and it was the most common stool in the community canteen.
Gu Chen put on his white gloves and turned off the strong flashlight.
At this moment, in the dark bathroom, Gu Chen found many luminous places around the stool.
Gu Chen turned the stool over and could clearly see that the back of the stool had the most fluorescence, indicating that the most blood stains had remained on it, as well as some tissue objects.
And all of this is generally something that ordinary people cannot see.
"This bathroom looks very clean, which shows that this guy has done a very thorough cleaning job." Gu Chen couldn't help but frowned.
But after turning the stool over, Gu Chen still hesitated, feeling that he should take the stool back for testing.
So Gu Chen first put the stool aside and started to check the sewer pipe of the bathtub.
Gu Chen gently unscrewed the cap of the sewer pipe. Under the illumination of a strong flashlight, he used his expert observation skills and found that there were more tissue fragments stuck inside.
Different from the small tissue fragments found on the wooden bench just now, there were quite large tissue fragments stuck to the cover of the water pipe.
Of course, to Gu Chen, any fragment larger than a small patch is considered quite large.
But the fragment that Gu Chen found was as big as the tip of a little finger. Seeing this scene, Gu Chen couldn't help but shudder in his heart.
"So... what's stuck to the wall of the sewer pipe is a piece of human tissue?"
Taking a breath of cold air, Gu Chen looked back at the living room, feeling doubtful 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: "Junior Brother Gu, did you find anything new in the bathroom?"
"There is a lot of fluorescence in the bathroom, indicating that someone has cleaned blood here, and there may be some tiny human tissue left on the wooden bench."
"Human...human tissue? Real or fake?" Lu Weiwei was also startled by Gu Chen's words, and her eyes were stunned.
Gu Chen nodded silently and added: "And I suspect that the murderer moved the stool during the murder."
"He had no idea that when he grabbed the inside part of the stool, some evidence would be transferred to it."
"And the tissue fragments in the sewer pipes cannot be washed away along the sewer pipes due to their different sizes. They are firmly adhered to the walls of the sewer pipes."
"If we combine everything found here and provide enough samples for the technical laboratory to conduct DNA testing."
"I think the test results will be what I imagined. This is most likely Zhang Lan's DNA."
"Yes." Lu Weiwei said with great certainty: "We can extract DNA from these tissues and compare it with the DNA of Zhang Lan's father. If these samples are really consistent with the DNA sample of Zhang Lan's father, then
We have enough evidence."
"Take that wooden bench 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, Officer Wang quickly asked, "How is it?"
"There was a large amount of blood residue in the bathroom, and we found objects suspected of human tissue on the inside of the wooden bench in the bathroom and on the wall of the sewer pipe."
"Human... human tissue?"
Upon hearing this professional term, Lu Min and He Lu couldn't help but look at each other.
The two quickly understood what Gu Chen meant. They were so frightened that they stared at each other and hugged each other.
"How...how could this happen? Why is there so much blood? Why is there still human tissue?"
"Could it be that Zhang Lan... is she really dead?"
"Oh my god! How could this happen?"
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 rag collector." After hearing what Gu Chen said just now, Zhu Lei panicked.
Facing Gu Chen's sharp eyes, his legs even became weak and his eyes kept averting.
"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 panicking at this moment, and they no longer dared to stay in this dry underground 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 underground floor and continued to collect strong evidence in every corner of the room.
Soon, Lu Weiwei seemed to have made a new discovery. She waved to Gu Chen: "Junior Brother Gu, come here quickly. There seems to be a knife under this wooden cabinet."
"Let me see." Gu Chen knelt down and quickly took the sharp weapon from Lu Weiwei's hand.
This was 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 something.
However, what surprised Gu Chen was that the fluorescent agent on the blade did not seem to have much effect.
Gu Chen couldn't help but frowned: "Is it because the things on it have decomposed?"
"Judging from the blade, it is obviously used. Look here, the blade has gaps." Lu Weiwei pointed at a gap and said.
Gu Chen nodded slightly and said, "Yes, there are signs that there is a small amount of blood on the machete."
"But maybe because there was too little blood, the fluorescent agent didn't seem to have much reaction."
"Then try again with the reagent." Officer Wang said.
Gu Chen nodded in agreement, thinking that if he could test the blood DNA bit by bit on the blade, many problems could be solved.
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