The matter of reconstructing the scene can actually be understood as, let me imagine committing a crime.
To put it simply, it means where I enter the scene, whether it is from the door or the roof, from the window or the floor, or I can follow the example of a medieval assassin and make a retrograde attack from the bottom of the aqua toilet.
The way to enter the scene can also be imagined, the actions within the scene can also be simulated, and the same is true for the way and location of leaving the scene.
If there is enough blood for bloodstain analysis, Jiang Yuan can reconstruct the scene very beautifully, because the blood can simultaneously show the position, speed, and acceleration of the murderer and the victim.
To be honest, the skill of bloodstain analysis is sometimes better than installing several detectors on the murderer, and is even more specific and real than what the camera captured.
Of course, this is the best situation.
General criminal investigators can only complete two ends. The middle part of the murder, especially the specific actions and steps of killing, basically does not involve too much. That part can be completed by forensic doctors.
Well, in the end it belongs to Jiang Yuan.
As for the scene this time, there was not much blood, and there were actually very few clues given.
But for Jiang Yuan, the only blood stains also revealed a lot of problems, such as the murderer's movement. He most likely came in through the door, and after two or three steps, he started to accelerate, and directly knocked down the cashier with a stick.
, and then swipe again.
Judging from these two decisive actions, the murderer is very decisive. He probably knows that there is money here, and may even have planned it for a long time.
Jiang Yuan looked in the direction where the blood spattered and saw that the murderer should be carrying a murder weapon. He collected the money and continued to move forward...
Ahead is where the window is.
Jiang Yuan stood still, tilted his head and asked He Guohua: "How did you judge the murderer's movement, where did he come from, and where was he going?"
He Guohua was already a little lonely waiting, but when he heard the question was so basic, he just thought Jiang Yuan asked it casually, and said: "Come in through the gate here, beat the cashier to death, pretend to take the money, and then
Run out again?"
His tone was uncertain. That was the case, and there weren't many signs in the room indicating the murderer's movements.
Whether it is crime scene investigation capabilities or blood stain analysis capabilities, there is an obvious gap between everyone.
Jiang Yuan didn't give in anymore and said directly: "The murderer jumped from the window."
"Ah..." He Guohua was stunned for a moment, took two steps forward, suddenly stopped, turned around and went to the door to bring several transparent acrylic stools over, and spread a few against the window before standing there.
Look out the window below.
"Is this footprint where the murderer landed?" He Guohua was a little surprised.
The problem now is not that there are no footprints, but that there are too many footprints to identify. If we can determine which footprint belongs to the murderer, it will be a big breakthrough.
Wang Bo, a former high-latitude creature, was not overshadowed by Master's surprise. He asked with the spirit of independent thinking: "Master, the first thing to determine is not the murderer's movement line. Why did the murderer jump from the window?"
.”
"Master Jiang already said that he jumped from the window." He Guohua glared at his apprentice, then looked out and said: "Look at the footprints below, do they look like the footprints of a jump? Would a normal person jump from the second floor?
?”
"It's possible that someone might jump out of the first-floor window..."
"The windows on the first floor are welded with steel bars. I want you to pay attention. What are you seeing with your eyes?" He Guohua turned around and scolded his apprentice.
Xiaobo originally wanted to question Jiang Yuan, but his business strength had not yet been trained, and he was hit by dimensionality reduction here in He Guohua.
Wang Bo wanted to struggle, and then said: "The medical examiner Jiang didn't look downstairs just now..."
"Doesn't that further prove that Mr. Jiang is awesome?" He Guohua was completely in the online state, looking at Wang Bo as he looked at the enemy keyboard player.
Wang Bo shrank his neck and just muttered: "If he doesn't take a good route, no one will notice him. Why doesn't he go through the door?"
This question is where the difficulty lies. He Guohua looked directly at Jiang Yuan.
Jiang Yuan spread his hands and said: "I can't tell for the time being, but based on the analysis of the traces at the scene, the murderer did this."
In fact, if you want to guess, there can be many reasons. For example, the murderer is a parkour player and will walk in places like this instead of walking on good roads; or the murderer gets excited and jumps directly; or the murderer just wants to use this method to confuse people.
Investigation; or there may be more than one murderer, and someone temporarily decides to take advantage of the evil...
Jiang Yuan has no evidence to reason about this yet, and he doesn't want to speculate about it yet.
His goal is to solve the case, not to convince a young man like Wang Bo. If the latter is too troublesome, he can just replace him.
He Guohua was much more obedient, and immediately followed Jiang Yuan's train of thought, saying: "In this way, the murderer can be assumed to be a young man first. Relaxing a bit, to someone in his thirties or forties, under normal circumstances,
You shouldn’t choose to jump out of the window.”
"My age is about thirty years old." Jiang Yuan also walked to the window, looked at the footprints on the ground from top to bottom, made a judgment, and said: "First collect the footprints below, and then go up to find the corresponding ones.
of."
The footprints downstairs were caused by jumping, and the marks are quite clear. Correspondingly, although the footprints cannot be seen on the floor upstairs, as long as they are collected, there will still be marks, but it may require the cooperation of some instruments.
Thinking of Jiang Yuan's ability to identify footprints, He Guohua's fire of hope was already burning brightly, so he picked up the survey box and left.
The sooner you can collect footprints, the better, especially outdoor footprints, which may be wiped out by a wind or a rain.
Nowadays, murder cases are relatively easy to solve. In fact, there is a reason. Murderers generally like to commit crimes indoors. According to statistics, the most common places to commit crimes are in their own homes.
This creates a situation where traces of crime are particularly difficult to remove. For example, blood stains that remain indoors may still remain after ten years. In the wild, it only takes months or weeks.
Time is basically eliminated.
Of course, there are too many cameras outside, which is the main reason why everyone makes this choice.
Changyang City has an electrostatic adsorption instrument that is professionally used for footprint extraction. It is actually a palm-sized instrument with a few knobs on it, which can be adjusted slightly.
He Guohua went downstairs and took a few photos of the footprints. Then he took out the electrostatic adsorption device and put it aside. He then took out a piece of insulating paper and covered it with the footprints.
The insulating paper is black, somewhat similar to old-fashioned carbon paper.
It itself is full of static electricity, shaking in an unruly manner.
After placing the insulating paper, He Guohua attached the two corners of the electrostatic adsorption device to the insulating paper, grounded one leg, and turned on the switch of the electrostatic adsorption device. The insulating paper immediately stuck to the ground.
"Roller." He Guohua stretched out his hand, and the young apprentice next to him immediately handed it to him.
He Guohua held the roller, pushed it gently on the insulating paper a few times, and explained to his apprentice: "Just push it flat. Don't use too much force. You will need to use glue later."
"oh."
Wang Bo nodded.
He Guohua handed the roller back to his apprentice, then gently peeled off the insulating paper. Using the angle of the light, he took a look and saw that the footprints had been clearly copied on the insulating paper.
He Guohua put the insulating paper into a box and processed it when he returned to the laboratory.
Later, He Guohua took out the adhesive again.
The adhesive is a piece of black adhesive paper, the size of a standard A4 paper, looks like sticky mouse paper, and the surface is also pitch black.
The adhesive is even simpler to use. It can be directly covered on the footprints. You can also brush it with a roller or even press it twice with your hands and pull it up directly.
However, after the adhesive treatment, the footprints on the ground will be damaged, which is why it is necessary to do the static electricity first and then the adhesive.
Returning to the crime scene upstairs, He Guohua then turned on the investigation light, adjusted the light source, and swept away the footprints on the ground.
Even if the footprints on the ground are invisible to the naked eye, they will be clearly visible when struck with a survey light.
Exploration lights all have variable light length. If you really can’t see, you can also adjust the wavelength, but generally speaking, white light is enough.
He Guohua continued to collect the footprints.
Looking up again, he saw Jiang Yuan staring blankly at the window.
"Brother Jiang, the sweep is finished." He Guohua reported.
"Well... have you scanned the window frame? Did you get any fingerprints?" Jiang Yuan gestured with his hand.
The window frame is made of plastic, which makes it difficult to take fingerprints.
He Guohua smiled and said: "I have taken fingerprints, but I don't know if there is a murderer."
"Then let's get it again." Jiang Yuan then asked for the survey box and started cleaning it.
He Guohua hesitated: "Do you think the murderer touched this window frame?"
"You can try to simulate it. Hold the murder weapon in one hand and jump out of the window. Can you avoid hitting the window frame?" Jiang Yuan gestured.
He Guohua also started gesticulating and couldn't help but murmured to himself: "It's really..."
Wang Bo said softly: "I can stay two meters away from the window, jump hard, lift my feet off the ground, pass through the window, and then land on my legs..."
Wang Bo not only spoke orally, but also moved his body. His feet were dangling on the bridge, but they were not crooked.
He Guohua said helplessly to Jiang Yuan: "He minored in gymnastics. He is a national first-class athlete."
Jiang Yuan could only click his tongue twice and said: "Is it rolled like this... If it's at the national level, let him go get some toner for the printer."
"Uh... ok. Can it be used to swipe fingerprints?" He Guohua asked, but without waiting for an answer, he sent Wang Bo out.
In the blink of an eye, Wang Bo was seen running in the sun.
Jiang Yuan nodded and said: "This kind of plastic material is very unlikely to show fingerprints. You can use printer toner mixed with magnetic powder to brush it."
Jiang Yuan was talking about some tips, and He Guohua quickly wrote them down. On-site exploration is all meticulous work, and the real test is actually in these small places.
Recommended book: "Cultivation in a leisurely manner in the city", urban cultivation is at the same level.
