civil forensic

Chapter 307

"I confirmed with the deceased's husband that the family's smart home can not only control the lights, but also turn on the bathroom heater and exhaust in one line. In addition, the air conditioner and fresh air system can also be used. The hood and bathtub are also controlled, including water intake and ventilation. put water...

Captain Ma returned to the scene. While talking about the situation, he couldn't help nagging: "Why would someone put all their home appliances online? Not only is it controlled by others, but they also have to spend more money on their own?"

"It should be very convenient. One-click hot water. When you are sitting on the subway, the bathtub in the bathroom has already started to store water. When you get home, you can take a bath directly. Isn't it wonderful?" Tang Jiadi One stood up and objected, which was something she would have liked to do.

Captain Ma pouted: "As for fighting for a few minutes..."

Wan Baoming hurriedly said: "I called the technology to come over. I'll see if I can find someone who has used this software. If the other party just uses it normally, they should leave traces."

Jiang Yuan listened to a few people talking, still silently sweeping the bathroom.

Regardless of whether the murderer used this system or not, he had actually done the murder and faked the suicide scene, and he had to do it in this bathroom.

In this way, the probability of leaving traces is also greatly increased.

Moreover, Jiang Yuan doesn't believe that someone can cover everything.This person spends all his time and energy on forging the scene, but he may not have enough time and energy to eliminate traces.

Many people have great misunderstandings in thinking and doing things. It seems to say, how much effort and time will it take to kill a husky by one person, hang it up, and pretend that it hanged itself?
What about cleaning the bathroom?Many people may have never tried to clean a bathroom in their entire lives. If they want to clean all the corners of the bathroom without leaving any traces, how much time and energy will it take?In the middle of the physical strength, I fell, broke my elbow, and had to clean it again. Some wayward players might just give up.

Give up or give up, see you on the execution ground.

The above are still murderers who can do things. Some murderers have obvious shortcomings in life, and it is even more difficult to kill people to remove their marks.

For example, some people don’t know how to tie a rope well, and they can’t fix the buttons for hanging themselves. When lifting a dead body weighing more than 100 kilograms, they are sweating profusely, and they have to be careful not to stain the clothes of the dead body. The rope opened, and the body fell to the ground, how angry and difficult!

In addition, if the murderer wanted to forge the scene, many methods would not be available.

For example, some cleaning products can indeed destroy DNA, but they are not commonly used cleaning products, or the victim did not buy them at home, so the murderer may only take the risk of leaving his own DNA behind.

This is a risk that has to be faced while falsifying the scene to obtain benefits.

Jiang Yuan is now blocking the murderer from cleaning up the scene.

His LV4 crime scene inspection skills can easily find problems in LV2 crime scene inspections.

An ordinary murderer, if he had not received professional training, why would he not leave any traces.

Of course, nowadays people who are knowledgeable can wear gloves, and there is a high probability that there will be no fingerprints.Jiang Yuan swept away a lot of dandruff and hair on the scene.Especially in the sewers and washbasins, short hair was taken out, and water stains were also wiped.

The deceased had long hair, and his daughter also had long hair, and lived in school.The husband of the deceased was half bald, and the length of the surviving hair was relatively long.

The source of this short hair is more thought-provoking.

Jiang Yuan carefully took a number of short hairs, put them into evidence bags, checked all kinds of toiletries, and then wiped a box of cotton swabs on various suspicious places, feeling a little more comfortable.

Compared with the identification of the time of death, the acquisition of such evidence seems to be more real.

"It's almost there." Jiang Yuan put the towel and other items directly into the large evidence bag.

To solve the murder case, there is no need to save money for the criminal police detachment.

Killing people is actually quite tiring. Refer to killing a 100-pound husky, and then hang it up to pretend to commit suicide.

The environment in the bathroom is airtight, and it is normal to sweat from exhaustion.

If the murderer wiped his sweat, there may be the murderer's DNA on the towel.If the murderer allowed the sweat to drip, the water stains on the many grounds just wiped may contain the murderer's DNA.If the murderer washed it directly with water, there might be his DNA in the sink he just wiped.

The strength of DNA is that it is extremely small. In an environment like the bathroom, unless cleaning and disinfection items are used reasonably, DNA may still remain even if it is washed with water many times.

But in order to fake the suicide scene, the murderer cannot use unconventional cleaning agents, which has the possibility of leaving DNA.

Such is the asymmetrical battle between the murderer and the police.

If the murderer chooses to falsify the scene, he cannot eliminate the evidence.If the murderer chooses to eliminate the evidence, he faces the risk of oversight, the hassle and professional requirements of carrying various cleaning items.Likewise, he faces the risk of omissions.

Of course, he can also choose not to deal with the scene and use the shortest contact time and contact method.But murderers, in many cases, are actually venting their emotions. Since they can't control their emotional venting, they may not be able to maintain considerable discipline when killing.

On the other hand, the shortest contact time and contact method also have to face the street cameras, possible witnesses, and the victim's resistance.

Just like Jiang Yuan's previous 513 door stabbing case, it was already a short-term contact case with luck superimposed, but after two or three layers of window paper were pierced, there was still a lot of evidence left.

However, if Jiang Yuan hadn't appeared to identify the time of death of the corpse, making her husband the first suspect, then the surveyors probably wouldn't have tried their best to collect evidence.

Because the husband's DNA must be all over the bathroom, as for whether there is other people's DNA, it is usually not investigated.

Who doesn't come to the two of them, leaving some beads of sweat in the bathroom.

The detectives of the criminal police detachment continued to be busy in the living room and bedroom, hoping to collect something else.

A murder case is different from other cases in that it usually has a stronger motive.Without sufficient motivation and anti-social personality, he will not kill easily.

As for cases of forged scenes, once the veil of forgery is lifted, the content usually becomes straightforward.

It was as if at the beginning, everyone was staring at the husband of the deceased.

If the deceased was not killed by her husband, then the murderer must have a strong relationship with her.

During the busy time, the technicians from the Internet Security Brigade arrived.

Similar to the investigation box of the current survey or the forensic investigation box of the forensic doctor, the technician who works on the network also has his own investigation box, in which the equipment for "violent" data acquisition is necessary, usually used to deal with mobile phones, and other smart devices will naturally escape. not drop.

Jiang Yuan and the others went out of the room and waited.

The family members of the victim and several neighbors were taken to the case handling center to make notes.

The corridor was quite quiet for a while, Wan Baoming looked around at this time, and said: "If it is not a smart home, the ventilation pipes and the like here should be hiding people by now."

"Hiding the corner, do you want to jump down after we leave?" Captain Ma was quite cooperative.

"Maybe the police were called too quickly."

"By the way, the husband of the deceased returned home faster than normal this time."

"It's useless to come back soon, and it's relatively rare to call the neighbors without saving people first."

Several people were talking at the door.

Soon, the technician came out, looked at the record in his hand, and said:
"It is true that at 10:21, someone turned on the Yuba, lights, and awning, and the air conditioner was heating. At 11:20, the awning was turned off, and the bathtub was controlled to discharge water. At 11:25, the exhaust fan was turned on, and the air conditioner was adjusted. The air supply volume of the fresh air system was reduced, and the air conditioner was changed to refrigeration. At 11:35, the Yuba was turned off, and the exhaust fan and air conditioner were turned off."

Captain Ma's face was serious: "Someone really took advantage of this thing."

Wan Baoming's expression was also ugly, and he looked at the technician: "Can you find out who controlled it?"

"You can only check it when you go back. If the other party is prepared, they may not be able to check it." The technician said.

Tang Jia said at this time: "Can I see the people who have connected to the wifi before? The records on the router or something like that."

The technician said: "You can see, what are you looking for?"

"Murder always has a reason. If it's not a property dispute, is it possible that this kind of murder is due to emotional problems?" Tang Jia said in a low voice: "The murderer is very clear about the situation of the deceased's family. Only when you have been here, you will know that there are these smart homes..."

"Okay, let's check according to this idea." Captain Ma nodded immediately, and continued: "Find someone, compare it with the DNA found at the scene, and see if you can match."

　See some readers ask if the formula in the previous chapter is true.Since the formula has been written into the book, it must be true. In fact, it was originally intended to respond to the reader's comments in the previous chapter, which is the judgment standard for the protagonist's death time identification.Originally, I felt that writing formulas would affect reading, and everyone was interested, so I wrote it.Of course, this formula is actually only one of a series of formulas, or one kind, not all of them.The source of the formula is "Applied Research on Estimating Time of Death by Rectal Temperature of Corpse in Guangzhou Area", "Chinese Journal of Forensic Medicine", Volume 2020, Issue 35, 5. There are many authors, so I won't write it here.Readers who encounter the need to apply this formula can... turn themselves in.

　
(End of this chapter)