The office space was limited. Faced with Zhao Heng's mysterious poisoning death, the only thing Gu Chen could think of was the method of committing the crime. As for the identification, the technical department of the city bureau was naturally responsible for completing it.
If the modus operandi cannot be discovered, there will be no evidence to convict the murderer.
"Gu Chen, just say whatever comes to your mind. There are no outsiders here." Officer Wang's depressed mood seemed to be relieved by this.
He knew that Gu Chen seemed to have made some new discoveries.
"Wait a minute." Gu Chen did not answer immediately, but handed the account book information sent by Zeng Ke to Forensic Doctor Liu: "Forensic Doctor Liu, can you help me check this account book?"
"Check the ledger?" Comrade Liu, a senior forensic doctor, was slightly confused for a moment: "Gu Chen, I can't read the ledger."
"You don't have to understand." Gu Chen smiled lightly and said, "I mean, you just need to check for me whether it contains any highly toxic substances?"
"So that's it." Forensic Doctor Liu felt that he and Gu Chen's ideas were somewhat deviated, and said awkwardly: "That's easy to say."
Then he called the forensic assistant: "Xiao Wu, help me get the tool box."
While Forensic Doctor Liu was preparing, Gu Chen was not idle either. He took out a glass of water from the water dispenser, put it on the table and said, "Senior Sister Lu, can you help me get the information book next to Zhao Heng?"
"Is it this one?" Lu Weiwei was a little hesitant. She was still not sure whether Gu Chen's move was effective, but she still handed over the account book.
Gu Chen opened the information book and soaked the footer parts in the water one by one.
"There are residual substances on it, right?" Officer Wang asked through gritted teeth. He felt that he was suddenly marginalized.
"Maybe this substance is colorless and odorless, so we can only try it first." Gu Chen replied lightly.
Any doubts must be verified before they can be called evidence.
What Gu Chen has to do now is to verify whether his reasoning just now is correct.
You know, in a closed office, there are only these people coming in and out.
To say that Zhao Heng was poisoned and died shortly after the three people left, the only possible clue is that he was exposed to some colorless and odorless substances, which led to poisoning and death.
Seeing Gu Chen soaking the footer of the information in clean water, Officer Wang could probably guess the reason why Gu Chen did this without Gu Chen's explanation.
"Gu Chen." Officer Wang squeezed to his side, staring at the information book to prevent himself from being marginalized.
Gu Chen moved a small step, gave up a position, and asked: "Senior Brother Wang, is there something wrong?"
Then he continued to operate seriously.
Officer Wang looked at Gu Chen so seriously and couldn't help but said: "Do you think Zhao Heng was poisoned and died because he touched the footer of the information with his hand?"
"Senior Brother Wang, you finally guessed it." Gu Chen smiled lightly, then threw the soaked information book aside.
"I think it should be coated with a colorless and odorless highly toxic substance. It's not the same kind of poison at all as the bottle of poison we found next to Zhao Heng earlier."
"I understand, you are saying that the bottle may be a deception, and what really caused Zhao Heng's poisoning and death may be the highly toxic substances left on the account information, and Zhao Heng's habit of licking his hands with his tongue led to his contact with
Is the highly toxic substance arriving at the footer of the ledger correct?”
Lu Weiwei followed Gu Chen's prompts and quickly followed the idea.
Gu Chen nodded: "Senior Sister Lu is so smart."
Receiving this compliment, Lu Weiwei felt like she was about to fly, and her heart felt warm.
Later, Gu Chen handed the remaining water to Forensic Doctor Liu.
The forensic assistant looked stunned and couldn't help but said: "Gu Chen, you are stealing my job."
It's clear that forensic assistants also feel marginalized.
The technical department has a division of labor and is generally composed of several senior forensic doctors, with assistants allowed.
But for Jiangnan City, which has a population of nearly 10 million, the scale of the technical department is larger than that of ordinary counties and cities, and it has access to more things.
Forensic Doctor Liu currently has two forensic assistants on hand to form a working group responsible for the daily work of the police stations in each district of the city.
Curbing his lips, forensic doctor Liu called to the forensic assistant: "Xiao Wu."
"Master, I'm here." The forensic assistant hurried up.
"Be proactive in your work. Don't wait for things to be done. Take the initiative to find work. In my opinion, you lack Gu Chen's enthusiasm."
I originally thought I would come over because I had something to do, but I didn't expect that I would be reprimanded and the forensic assistant was drunk.
Forensic Doctor Liu has always disliked lazy assistants, especially his own work, which ended up being taken away by other departments.
"Yes, master." The forensic assistant nodded, and then...he stared at Gu Chen fiercely again.
Gu Chen's operation is very simple. It is a simple chemical reaction method that uses a chemical reaction between a solution and the substance to be detected. By observing the reaction, the color and state of the reactant are used to determine whether there is a certain substance.
This kind of basic operation can be understood by ordinary professionals at a glance, but Gu Chen is a trainee police officer and has nothing to do with forensic science.
Being able to understand this is already very valuable.
Forensic Doctor Liu even came up with the idea of replacing his apprentice.
"Young people should learn more skills." After putting away the tools in his hands, Forensic Doctor Liu couldn't help but ask again: "Gu Chen, have you learned these?"
"No." Gu Chen shook his head.
"Gu Chen usually goes to the library after get off work. I guess I saw him there." Lu Weiwei, who had been silently paying attention to her junior brother, said casually.
"It would be good to know this." Forensic Doctor Liu also explained it while doing the operation.
“In our forensic testing, we generally use chemical reaction methods, which have the advantages of being easy to operate, fast, and less restricted by time and place. However, they are not very sensitive and specific. They are generally only used as preliminary experiments to narrow the scope of toxicant analysis.
"
Gu Chen listened very carefully: "It seems that chemical reaction methods are rarely used now, but in some cases, they can be used for confirmatory analysis."
"That's right." Forensic Doctor Liu nodded: "For example, based on the Prussian blue reaction, it is judged whether the test object contains cyanide, according to the Grignard reaction whether the red color appears, and whether there is nitrite in the test solution. These are all one
It makes sense.”
"But chromatography is more popular now." Gu Chen said again without warning. His mind was full of knowledge now, and it was really difficult for him to hold back.
"Chromatography is a separation analysis method." Forensic Doctor Liu took out the domestic Xinhua filter paper from the tool box and asked casually: "Do you know which number you use?"
Gu Chen hesitated for a moment and smiled lightly: "No. 1 11μm is the most commonly used in daily filtration. It has a medium retention flow rate and is widely used in laboratory applications to clarify liquids and is typically used for sediments.
Quantitative analysis of separations such as lead sulfate, calcium oxalate and calcium carbonate."
Forensic Doctor Liu chuckled and said calmly: "You are right, but are you sure you use this number?"
Although what Gu Chen said was quite reasonable and detailed, it seems now that he only had a superficial understanding.
But these are already very rare in Forensic Doctor Liu's mind.
"No." Gu Chen shook his head and smiled: "If it were me, I would choose No. 5, which is 2.5μm."
Forensic Doctor Liu was stunned: "Keep talking."
"Because this is the most efficient qualitative filter paper." Gu Chen paused and said with some thought: "It can be used to collect small particles and has a slow flow rate. It is suitable for chemical analysis, clarification of suspended solids and analysis of water."
When Gu Chen said this, everyone present was stunned, and the forensic assistant standing aside immediately hated him even more.
