Rinsing the blood agent with clean water can only clean the platelets, but cannot completely clean the DNA or protein substances in the blood.
To put it simply, rinsing the blood with water can only wash away the color. On the surface, it looks like there is no blood, but in fact some substances contained in the blood will still remain on the carrier.
To thoroughly clean away blood stains, you need to use some special cleaning substances.
This special cleaning agent is not a single cleaning agent, but a mixed cleaning agent.
In most cases, ordinary laundry detergent plus decomposing protease, and then mixed with some water, can clean away traces of blood more thoroughly.
The reason why protease is added is because the blood contains a large amount of protein material. It is because of the existence of this protein material that the DNA information in the blood can be detected.
The use of decomposing protease can effectively decompose protein substances in the blood.
As for using laundry detergent, it can dissolve grease, which allows the damaged protein substances to be dissolved in water and then washed away.
Of course, the specific protease content and the ratio between the amount of laundry detergent and the amount of water are more stringent, so that the remaining traces of blood can be thoroughly washed away.
It is impossible for ordinary people to master it.
The murderer who killed Zhang Xiaotian's four people obviously did not have such a reserve of skills. He just used water to roughly deal with the blood stains.
Of the two pillows on the bed, the pillow cover on one of them disappeared. It is possible that the pillow cover was used by the other person to wipe the blood stains.
They should have been taken away by the other party afterwards.
In addition, Lu Chuan also found some bloody footprints at the scene.
“Is the murderer a woman?”
The coagulated blood did not contain the footprints of the two murdered men, as they had been fatally struck by a single blow, but there were the footprints of the two murdered women.
It is also easier to identify. The two murdered women did not wear socks or shoes, and the footprints left behind were barefoot footprints.
Based on the circumstances discovered so far, it can be roughly analyzed that the murderer entered the room while the four people were sleeping, and immediately attacked the two men, directly cutting their carotid arteries and killing them with one knife. .
Afterwards, the two women were probably awakened by the murderer, and a fight took place.
During the struggle, the murderer stabbed the two female victims with a sharp knife.
Among the footprints left in the pool of blood on the ground, in addition to the barefoot footprints, there is also a set of footprints that should be the murderer's footprints. They are quite special. The forefoot and back heels are the footprints left by high heels.
That’s why Yang Sen said the other party was a woman.
However, the physical characteristics of the murderer given by Lu Chuan based on the footprints were like this.
"With size 43 high heels, the murderer is 1.78 meters tall and weighs about 70 kilograms."
If the murderer is really a woman, then the murderer is indeed taller than a woman. It is relatively rare among them.
Of course, it is not ruled out that the murderer is a man and deliberately wore high heels to hide his true footprints.
The next work is more detailed, collecting dander, hair, blood samples and other information at the scene.
Some blood and dander tissue were also found in the fingernails of the two female victims.
It is possible that during the struggle between the two parties, the two female victims scratched the murderer's skin.
“Passion kills?”
Although the scene looked bloody, there were actually quite a few flaws left by the murderer, whether it was blood stains wiped with clean water, footprints in a pool of blood, or blood stains and dander found in the fingernails of the two female victims.
Any clue can directly identify the suspect. Therefore, Yang Sen felt that the other party committed the murder out of passion. Otherwise, if it was a plot to kill, he would not have left so many obvious clues as long as he searched for more information on the Internet or watched a few movies.
“The probability of killing in passion may be higher, but it does not rule out that the other party has some plans. After all, judging from the time of killing, the other party came to kill in the middle of the night.”
"The four victims were all asleep at the time. The other party should have known the four victims in advance, or at least the homeowner, because at that time, it was impossible for them to have a direct conflict."
Of course, Lu Chuan said this, but he actually thought that the other party was a passionate murderer.
I just killed people on a whim without any planning.
The two of them were analyzing the case in a narrow room while collecting physical evidence from the current investigation.
This busy work lasted almost three or four hours.
After the two came out, they handed over to the forensic doctor before Wang Changjiang and Shen Yan went in.
"How is it?"
Qin Yong looked at Lu Chuan and asked about the current survey situation.
“A lot of clues were found. Based on the footprints left by the murderer, preliminary analysis shows that the murderer is 1.78 meters tall and weighs about 70 kilograms.”
“The shoe prints left by the murderer are high-heeled shoes. , but the size of the high-heeled shoes is very large, a full size 43. I am more likely to be a male murderer, who deliberately wore high-heeled shoes to commit crimes.” Five kilograms.”
"Captain Qin, it should be him, are you going to arrest him or not?"
Zhang Hui, who was standing next to Qin Yong, looked excited when he heard Lu Chuan's survey results.
Judging from the results of the peripheral investigation, Wang Junshan, who once lived with Zhang Xiaotian, is suspected of committing a major crime.
The personal information about Wang Junshan found by the detachment was also passed on. The height and weight of the other party were relatively consistent with the results of Lu Chuan's current survey.
“Have a goal?”
Lu Chuan knew as soon as he heard that Zhang Hui's visit and investigation had already targeted a person.
Zhang Hui nodded: "Zhang Xiaotian is gay, and the target suspect is most likely his partner who once lived with him."
"Lu Chuan, what else have you discovered here? "
"In addition to the footprints, the murderer probably shed his own blood at the scene. We have collected some samples and tried to do some identification and analysis of DNA information. We also found that the two female deceased Some blood and skin scrapings were found in the nails, which may have been left by the murderer."
"Great, you guys will get the results as soon as possible, Zhang Hui, arrest the person first!"< br>
"On Sun Jun's side, the surrounding surveillance cameras will be used to investigate and see if they can find a suspect with a similar build to the one given by Lu Chuan."
Although the surveillance of the building at the crime scene has been damaged, the surrounding roads The monitoring is good. The other party cannot appear out of thin air. There is less traffic in the middle of the night, so it is very possible to find clues about the other party.
In this way, through interviews and investigations, the target suspect and the evidence from Lu Chuan have been discovered, coupled with surveillance, the case can be confirmed.
While the forensic doctor was doing the examination, the investigator had already driven back to the criminal investigation detachment.
DNA identification analysis can be completed in about one day.
Zhang Hui found Wang Junshan in another rental house two hours later. (End of this chapter)