"I confirmed with the husband of the deceased that this family's smart home can not only control the lights, but also turn on the bathroom heater and exhaust system. In addition, the air conditioner and fresh air system can also be controlled. The shower head and bathtub can also be controlled, including the water inlet.
and release water...
Captain Ma returned to the scene and while talking about the situation, he couldn't help nagging: "How could someone put all their home appliances online? Not only did they let others control them, but they also had to spend more money themselves?"
"It should be very convenient. With one click of hot water, you can sit on the subway and the bathtub in the bathroom has started to fill up with water. When you get home, you can take a bath directly. Isn't it wonderful to think about it?" Tang Jiadi
One person stands up and expresses her opposition, which is what she is willing to do.
Captain Ma curled his lips: "As for fighting for a few minutes..."
Wan Baoming said quickly: "I'll call the technician to come over and see if we can find someone who has used this software. If the other party just used it normally, there should be traces left."
Jiang Yuan listened to several people talking and still scanned the bathroom silently.
Regardless of whether the murderer used this system or not, he definitely did 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 greatly increased.
Moreover, Jiang Yuan did not believe that anyone could cover everything. This person spent all his time on forging the scene, but he might not have enough time and energy to eliminate the traces.
Many people have huge misunderstandings in thinking and doing things. It is like saying that if you want to kill and hang a husky alone, you have to pretend that you hang yourself. How much effort and time does it take?
What about cleaning the bathroom? Many people may have never tried to clean a bathroom in their lives. If you want to clean every corner of the bathroom without leaving any traces, how much time and energy will it take? You will be exhausted in the middle.
If you fall down and break your elbow, you have to clean it again. Some willful players may just give up.
If you give up, give up, see you on the execution ground.
The above are still murderers who know how to do things. Some murderers have obvious shortcomings in life. It is even more difficult to kill people and remove traces.
For example, some people don't know how to tie ropes, and they can't fix the buttons for hanging. They lift a corpse weighing more than 100 kilograms, and they are so exhausted that they sweat profusely. They have to be careful not to get it on the clothes of the corpse. Then, there is a chirp.
, the rope opened, and the body fell to the ground, so angry, so difficult!
In addition, if the murderer wants to fake the scene, many methods will 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 have no choice but to risk letting his own DNA stay.
This is a risk that we have to face while gaining benefits from forging the scene.
Jiang Yuan is currently blocking the murderer and unable to clean up the scene.
With his LV4 crime scene investigation skills, he can easily find problems in crime scenes that have been investigated by LV2.
If an ordinary murderer has not received professional training, why would he not leave any traces?
Of course, nowadays, knowledgeable people can wear gloves, and there is a high probability that there will be no fingerprints. Jiang Yuan swept up a lot of dander and hair at the scene. Especially in the sewers and wash basins, short hair was picked up and wiped.
to water damage.
The deceased had long hair, and his daughter also had long hair, and she was staying at school. The husband of the deceased was semi-bald, and the remaining hair was relatively long.
The origin of this short hair is more thought-provoking.
Jiang Yuan carefully took out a number of short hairs and put them into evidence bags respectively. He also checked various toiletries, and then wiped a box of cotton swabs on various suspicious areas, feeling a little better.
Compared with the identification of the time of death, the acquisition of this kind of evidence seems to be more real.
"That's almost it." Jiang Yuan put the towels and other items directly into the large evidence bag.
By solving the murder case, there is no need to save money for the criminal police detachment.
Killing is actually quite tiring. For example, kill a 100-pound husky and then hang it up to pretend to commit suicide.
The bathroom is an airtight environment, so it's normal to break out in a sweat.
If the murderer wiped his sweat, then the murderer's DNA might be on the towel. If the murderer allowed the sweat to drip, then the many water stains on the floor just wiped might contain the murderer's DNA. If the murderer washed it directly with water, then
There might be his DNA in the washbasin you wiped just now.
The great thing about DNA is that it is in extremely small amounts. In an environment like the bathroom, unless cleaning and disinfecting items are used properly, DNA may still remain even if it is rinsed with water many times.
Unfortunately, in order to fake the suicide scene, the murderer could not use unconventional cleaning agents, which gave rise to the possibility of leaving behind DNA.
This is the asymmetric battle between the murderer and the police.
If the murderer chooses to forge the scene, he cannot eliminate the evidence. If the murderer chooses to eliminate the evidence, he will face the risk of omissions, as well as the trouble and professional requirements of carrying various cleaning supplies. Likewise, he will also face the risk of omissions.
.
Of course, he can also choose not to deal with the scene and use the shortest contact time and method. But most of the time, murderers are actually venting their emotions when they kill people. Since they can't control their emotional venting, they may not be able to kill people.
Maintain considerable discipline when doing so.
On the other hand, the shortest contact time and method also require facing street cameras, possible witnesses, and the resistance of the victim.
Just like Jiang Yuan's previous 513 door-to-door stabbing case, it was considered a short-term contact case with a combination of luck, but after two or three layers of window paper were pierced, there was still a lot of evidence left behind.
However, if Jiang Yuan had not appeared to identify the time of death of the body, making her husband the first suspect, then the investigators probably would not have worked so hard to collect evidence.
Because the husband's DNA must be all over the bathroom, as for whether there is other people's DNA, we usually don't delve into it.
Who wouldn't have two people come over and leave some beads of sweat in the bathroom?
Several investigators from the criminal police detachment continued to be busy in the living room and bedroom, hoping to collect something else.
Murder cases are different from other cases in that they usually have a relatively strong motive. Without enough motive, someone who is not an antisocial personality will not kill someone easily.
In cases of forgery, once the veil of forgery is revealed, the content usually becomes straightforward.
It was like 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 period, technicians from the network security team arrived.
Similar to the investigation box used by current investigators, or the forensic investigation box used by forensic doctors, network technicians also have their own investigation boxes, which must include equipment for "violently" obtaining data, which are usually used to deal with mobile phones, and other smart devices can also escape.
Don't fall off.
Jiang Yuan and others went directly out of the room and waited.
The victim's family members and several neighbors were taken to the case handling center to take notes.
The corridor was quite quiet for a while. Wan Baoming looked around and said, "If it wasn't a smart home, people should be hiding in the ventilation ducts in here."
"Hide around the corner and jump down after we leave?" Captain Ma was quite cooperative.
"Maybe the police were called too quickly."
"By the way, the deceased's husband came home faster than usual this time."
"It's useless to come back quickly, and it's also rare to just call the neighbors without rescuing people first."
Several people were chanting 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 bathroom heater, lights, shower head, air conditioning and heating. At 11:20, he closed the shower head and controlled the water discharge in the bathtub. At 11:25, he turned on the exhaust fan and adjusted
The air supply volume of the fresh air system was increased, and the air conditioner was changed to cooling. At 11:35, the bathroom heater was turned off, and the exhaust fan and air conditioner were turned off."
Captain Ma's face was solemn: "Someone really took advantage of this thing."
Wan Baoming also looked ugly and looked at the technician: "Can you find out who is controlling it?"
"You can only check it when you get back. If the other party is prepared, they may not be able to find 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 and so on."
The technician said: "You can take a look. What are you looking for?"
"There must always be a reason for murder. If it is not a property dispute, is it possible that this kind of murder is due to emotional issues?" Tang Jia said in a low voice: "The murderer is very clear about the situation in the deceased's family. At least he must
Only if you have been here, you will know about these smart homes and the like..."
"Okay, let's check according to this idea." Captain Ma nodded immediately, and then said: "Find the person and compare it with the DNA found at the scene to see if there is a match."
I see some readers asking if the formula in the previous chapter is true. Since the formula is written into the book, it must be true. In fact, it was originally in response to the reader's comment in the previous chapter, which was to determine the protagonist's time of death.
It is a matter of judgment criteria. I originally thought that writing a formula would affect reading, and everyone was interested, so I wrote it. Of course, this formula is actually just one, or one, of a series of formulas, not all of them. The source of the formula is "Guangzhou Area Cadavers"
"Application Research on Rectal Temperature to Determine Time of Death", "Chinese Journal of Forensic Medicine", Volume 35, Issue 5, 2020. There are many authors, so I won't write about it. Readers who need to apply this formula can... surrender.
