When he investigated the crime scene for the second time, Lu Chuan did it himself.
Lu Chuan conducted the entire on-site survey to the highest standards within his capabilities, so there were many things tested.
There are also more inspection stations sent to the criminal investigation detachment's current investigation office. Yang Lin has already worked an extra night, and it took two days and one night to basically finish all these things.
Among the clues discovered, there are conventional clues such as fingerprints and footprints.
In addition, there are some undried blood stains and some other sampling samples.
For example, Lu Chuan found some debris in the cracks of the bathroom floor and some debris found under the elbow of the kitchen sink and bathroom sink.
Because Wang Hong’s DNA information and related fingerprints and footprints have been collected in advance, some things can be eliminated quickly.
“Lao Lu, there are basically no clues in fingerprints and footprints. From what you collected, they are basically those of Internet celebrities. What I can compare here are basically his. There are no other strangers. "
Normally speaking, even if the murderer stayed in the room for a short time and did not leave many clues, there should be more people in the room belonging to Wang Lili and Wang. Red fingerprints and footprints of two people.
But now the fingerprints and footprints collected by Lu Chuan belong to Wang Lili, which means that the murderer must have carefully cleaned up the scene after killing the person.
Of course, when Lu Chuan conducted his second investigation, it was already a week after the incident, during which Wang Lili had lived in the room for two or three days.
However, with only two or three days, it is actually impossible to completely cover the traces of Wang Lili’s life.
Obviously the murderer did a more detailed cleaning.
"In addition, I have confirmed that the mop you brought back and the blood stains you wiped back from the bathroom are basically consistent. I can confirm that the mop is one of the tools used by the murderer to clean up the scene. I also said above Some remnants of blood stains were found.”
Yang Lin carefully inspected the mop brought back by Lu Chuan.
Although the murderer had cleaned the mop and washed it several times with clean water, there were still some iron ions and proteins in the blood because there were no traces of any strangeness on the surface.
Yang Lin just did some simple chemical experiments and the results proved that.
On the phone, Yang Lin continued to report to Lu Chuan on his side’s appraisal situation.
“The other party also cleaned the kitchen knife, and no traces of fingerprints or the like were found on it.”
Of course, that doesn’t mean there are no fingerprints on it at all, there are royal fingerprints on it. Red fingerprint.
According to Wang, he found the kitchen knife on the refrigerator while cleaning.
So the first person to take the kitchen knife was Wang Hong. He did find fingerprints left on it, but the fingerprints were not grip marks, but marks of fingers pinching the handle of the knife.
And on the other hand, if there really are no residual fingerprints on the kitchen knife, it can only mean that an internet celebrity is lying.
Because he must have touched the kitchen knife, and if there are no traces of him on it, it proves that Wang Hong has cleaned the kitchen knife.
So it is normal that Wang Hong’s fingerprints are on it. Without her fingerprints, there is a big problem.
Lu Chuan had actually expected this.
Since the murderer had carefully cleaned the scene, it was obviously unlikely that he would have left any traces of him on the kitchen knife.
"According to my experience, the curled blade on the kitchen knife should have broken open when the murderer chopped the bones. Have you looked at the molecular cells on it?" Lu Chuan asked.
This is a cutting-edge technology that has just emerged in recent years.
In fact, there are not many applications in the field of criminal investigation.
When Lu Chuan was just in the criminal investigation detachment, after Qiangsheng Group donated 100 million to the administrative detachment, Lu Chuan spent a small 10 million of it to purchase related equipment.
At that time, I felt very distressed for the detachment leader Qin Yong.
After all, the other equipment added up to less than 10 million yuan, but the small set of equipment that Lu Chuan built was not used much, and it actually cost eight to nine million yuan.
But at that time Qin Yong just felt distressed and didn't feel anything. After all, the money was donated by Qiangsheng Group. How Lu Chuan decided to spend it was of course his business, after all, he had already named it. It is used for the construction of on-site survey office laboratories.
It's just that the money can't be used so much, and a lot of other equipment has been added to the detachment.
Of course it has also improved the living conditions in many detachments.
The more expensive one is something called a flow cytometer.
This is an instrument that can quickly analyze a large number of cells.
It can reflect the cycle of cells by detecting the quantitative levels of cell surface markers.
Of course, this feature can also be used to label cells from different people. At the same time, fluorescence microscopes, confocal microscopes and other equipment can be used to study some functional states of different cells.
Specific fiber technology combined with a flow cytometer can label different cells in different people.
For example, analyze the kitchen knife.
Lu Chuan specifically told Yang Lin that this molecular cell test should be carried out on items such as mops and kitchen knives that were confirmed to have been touched by the murderer.
The main reason is that if the murderer really took this kitchen knife and mop, theoretically speaking, the cells of the other party's body would be in a state of metabolism at all times.
Then even if the other party cleans it thoroughly, it is very likely that its cells will be left on the surface of the mop stick and the surface of the handle.
In addition, because of the people who touched the kitchen knife, it is impossible that the murderer was the only person who took the mop. It is also possible that Wang Lili and Wang Hong were the two people.
So the most important thing is to distinguish the collected molecules and cells first.
This is the role of flow cytometers, fluorescence microscopes, confocal microscopes and other equipment. Cells are labeled and classified first, and then the next more important work is carried out.
“That’s what I want to say!”
Yang Lin's voice was slightly excited!
“According to the method you taught earlier, I have extracted several different types of cells from the mop rod and kitchen knife handle.”
This step actually consumes a lot of time in Liaoning. Labeling analysis of cells is a very detailed task, because from the cell itself, the composition and structure of human cells are basically the same.
It’s just that because different people’s DNA expressions are different, there will be some subtle differences in cells.
Of course, this most complicated step is not the most important, because Yang Lin's purpose is not just to separate the cells, but to obtain the DNA information material above. (End of chapter)