civil forensic

Chapter 298

The matter of rebuilding the scene can actually be understood as, let me imagine a crime.

To put it simply, it is where I enter the scene, whether it is from the gate or the roof, whether it is from the window or the floor, or imitating the medieval assassin and making a retrograde raid from the bottom of the dry toilet.

The way to enter the scene can also be imagined, and the actions in the scene can also be simulated, as well as the way and location to leave the scene.

If there is enough blood for bloodstain analysis, Jiang Yuan can reconstruct the scene very beautifully, because the blood can show the position, speed, and acceleration of the murderer and the victim at the same time.

To be honest, the skill of bloodstain analysis is sometimes better than installing a few detectors on the murderer, and it is even more specific and real than the ones captured by the camera.

Of course, this is the best state.

Ordinary criminal investigators can only complete the two ends. The murder part in the middle, especially the specific actions and steps of the murder, basically does not involve too much, and that part can be completed by the forensic doctor.

Well, in the end it was Jiang Yuan's.

As far as this scene is concerned, there is not much blood, and there are actually few clues given.

But for Jiang Yuan, the only bloodstains also explained a lot of problems, such as the murderer's movement line, he most likely came in through the door, and after two or three steps, he started to speed up, and directly knocked down the cashier , then swipe again.

Judging from these two decisive actions, the murderer was very decisive. He probably knew that there was money here, and it might even have been planned for a long time.

Jiang Yuan looked in the direction where the blood spattered out, the murderer should be carrying a murder weapon, gathered up the money, and continued to move forward...

The front is where the windows are.

Jiang Yuan stood still, turned his head and asked He Guohua: "How did you judge the murderer's movement, where did he come from, and where did he go?"

He Guohua had been waiting a bit lonely, but now he heard the question was so basic, he thought that Jiang Yuan was asking casually, and said: "Come in through the gate here, kill the cashier, pretend to take the money, and then Run out again?"

His tone was uncertain.That was the case at first, and there were not many signs in the room to indicate the murderer's movement.

Whether it is the ability to investigate crime scenes or the ability to analyze blood stains, there is a clear gap between everyone.

Jiang Yuan didn't hold back anymore, and said directly: "The murderer jumped from the window."

"Ah..." He Guohua was stunned for a moment, took two steps forward, stopped suddenly, turned around and went to the door to bring several small transparent acrylic stools over, spread a few near the window, and then stood window to see 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.It would be a big breakthrough to be able to determine which footprints belonged to the murderer.

Wang Bo, a former high-latitude creature, was not concealed by Master's surprise. He asked with an independent thinking spirit: "Master, first of all, it should not be the murderer's moving line. Why did the murderer jump from the window?" .”

"Master Jiang said he jumped from the window." He Guohua glared at his apprentice, then probed again: "Look at the footprints below, do they look like the footprints of jumping? Would a normal person jump from the second floor?" ?”

"People may jump out of the windows on the first floor..."

"The windows on the first floor are welded with steel bars. Let you pay attention to observe. What are you looking at?" He Guohua turned his head and scolded his apprentice.

Xiao Bo originally wanted to question Jiang Yuan, but his business strength has not yet been trained, and he was hit by dimensionality reduction at He Guohua's place.

Wang Bo wanted to struggle a bit, and said again: "Then forensic doctor Jiang didn't look downstairs just now..."

"Doesn't that mean that Master Jiang is a bull?" He Guohua completely entered the Internet mode, watching Wang Bo as watching the enemy's keyboard player.

Wang Bo shrank his neck and muttered: "If you don't take a good road, no one will find it. Why doesn't he go through the door?"

This problem is where the difficulty lies.He Guohua looked directly at Jiang Yuan.

Jiang Yuan spread his hands and said: "I can't say for the time being, but based on the analysis of the traces at the scene, the murderer did just that."

In fact, if you want to guess, there are many reasons.For example, the murderer is a parkour player, and if he does not take a good path, he will go to this kind of place; or the murderer is excited and jumps directly; or the murderer wants to use this method to confuse the investigation; or there may be more than one murderer , and someone temporarily decided to eat black and white...

Jiang Yuan has no evidence to deduce this for the time being, and he doesn't want to speculate about it for the time being.

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 it.

He Guohua was much more obedient, and immediately followed Jiang Yuan's train of thought, saying: "In this way, the murderer can be presumed to be a young man first. Let it be relaxed, people in their thirties and 40s, under normal circumstances, should I would not choose the path of jumping out of the window."

"Age is about 30 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 footprints." .”

The footprints downstairs were caused by jumping down, and the imprints are quite clear. Correspondingly, although no footprints can be seen on the floor upstairs, as long as they are picked, there will still be imprints, 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, so he picked up the investigation box and left.

The faster the footprints are collected, the better, especially this kind of outdoor footprints, maybe a wind or a rain will kill them.

Today's murder cases are relatively easy to solve. In fact, there is also a reason that murderers generally like to commit crimes indoors. According to statistics, the most crime locations are still in their own homes.

This creates a situation in which traces of crime are particularly difficult to remove.Like bloodstains, the bloodstains left in the room may still remain ten years later.Wherever it looks like in the wild, it doesn't take a few months, a few weeks, and it is basically eliminated.

Of course, there are too many cameras outside, which is the main reason why everyone makes this choice.

Changyang City has a professional electrostatic adsorption instrument for footprint extraction. It is actually a palm-sized instrument with a few knobs on it for a little adjustment.

When He Guohua arrived downstairs, he first took a few photos of the footprints, then took out the electrostatic adsorption instrument, put it aside, took out another piece of insulating paper, and covered the footprints.

The insulating paper is black, somewhat resembling old-fashioned carbon paper.

It itself is full of static electricity, trembling and unruly.

After placing the insulating paper, He Guohua stuck the two corners of the electrostatic adsorption instrument on the insulating paper, grounded one foot, turned on the switch of the electrostatic adsorption instrument, and the insulating paper was immediately attached to the ground.

"Roller." He Guohua stretched out his hand, and the little apprentice next to him immediately handed it to him.

Holding the roller in his hand, He Guohua gently pushed it on the insulating paper a few times, and explained to his apprentice: "Just push it flat, don't use too much force, and glue will be used later."

"Oh."

Wang Bo nodded.

He Guohua handed the roller back to his apprentice, and 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 in a box and processed it when he returned to the laboratory.

Afterwards, He Guohua took out the glue again.

The glue is a piece of black adhesive paper, the size of a standard A4 paper, it looks like sticky mouse paper, and the surface is also dark.

It is easier to use the glue, just cover the footprints directly, brush it with a roller, or even press it twice with your hand, and then pull it up directly.

However, after the glue treatment, even if the footprints on the ground are damaged, this is why it is necessary to do static electricity first, and then glue.

Back at the crime scene upstairs, He Guohua then turned on the survey light, adjusted the light source, and scanned the footprints on the ground.

Even if the footprints on the ground are invisible to the naked eye, they can be clearly seen with a search light.

All survey lights have variable light length, and you can use wavelength modulation if you can’t see them, but generally speaking, white light is enough.

He Guohua continued to collect footprints.

Looking up again, Jiang Yuan was staring at the window in a daze.

"Brother Jiang, the scan is over," 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, so it is difficult to take fingerprints.

He Guohua smiled and said: "I have got fingerprints, so I don't know if there is a murderer."

"Then let's take it again." Jiang Yuan asked for the survey box and started to brush.

He Guohua hesitated: "Do you think the murderer touched the window frame?"

"You can try to simulate it, holding the murder weapon in one hand, jumping out of the window, can you avoid touching the window frame?" Jiang Yuan gestured.

He Guohua also gestured, and couldn't help muttering 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 my legs land on the ground..."

Wang Bo not only dictated, but also moved his body. His feet dangled 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 so curly... If it is at the national level, let him run to get some printer toner."

"Uh... okay. Is it for fingerprinting?" He Guohua asked, and sent Wang Bo out without waiting for an answer.

In a blink of an eye, Wang Bo was already running in the sun.

Jiang Yuan nodded, and said: "This kind of plastic material is very difficult to swipe fingerprints. You can use printer toner mixed with magnetic powder to swipe."

Jiang Yuan talked about the little tricks, and He Guohua quickly wrote them down. On-site exploration is all about meticulous work, and the real test is actually these small places.

　Friendship push book: "Cultivation Leisurely in the City", the city's cultivation of immortality lies flat.

　　
　
(End of this chapter)