Chapter 370 Mathematical Solving the Case
Minors, after hearing this answer, both Fukiya Rei and Kazami Yuya fell silent.
This is indeed someone they "cannot afford to offend".
If the murderer is a minor, even if he is caught, he will not be punished as he deserves.
Lin Xinyi was even more troubled by it than them:
Because he already knows that the current (1996) Japanese law's stipulation on the age of absolute non-criminal responsibility is 2 years older than the 14-year-old criminal liability limit he knew -
Yes, Japan before 2000:
Minors under the age of 16 do not need to bear any criminal responsibility.
It was not until the "Kobe Child Serial Killing Incident" in 1997 that aroused strong social response that the Japanese Parliament lowered the minimum applicable age for criminal punishment from 16 to 14 in 2000.
In the "Kobe Children's Serial Murdering Incident", the murderer "Boy A" specifically selected elementary school students and used extremely cruel and bloody methods such as dismembering and mutilating the bodies to kill two people and seriously injure three others.
Because he was only 14 years old when he committed the crime, he was released from the juvenile reformatory hospital after being arrested for less than 7 years.
In 2015, the murderer "Youth A", who has long since returned to society, wrote an autobiography based on his own experiences and is said to have made a lot of money.
so.
Faced with minors committing crimes, Lin Xinyi only felt powerless:
"16 years of criminal liability"
"If my conjecture is true, then the murderer's biological age will definitely be less than 16 years old."
"That is, the only thing we can do."
"It means sending him to a juvenile reformatory to help him 'rehabilitate' and return to society in the future."
Lin Xinyi didn't know how effective the reform of the juvenile reformatory in Japan was.
But think about it, the effect of the thought transformation of the murderer "Youth A" who had the nerve to publish his autobiography and eat steamed buns with human blood when he grew up is very questionable.
"Forest Manager."
Feng Jian Yuya held a glimmer of hope and asked in a self-deceiving manner:
"Could the murderer really be a minor?"
"Could it be that you guessed wrong?"
"I also hope that I am wrong. But at present, the murderer is indeed a minor with a high probability."
Lin Xinyi replied in a difficult tone:
"First of all, the footprints left by the murderer on the lawn were of a smaller shoe size, which indicates that he is probably a petite woman or a minor."
"Secondly, the murderer hit the deceased twice with a metal hammer during the sneak attack, but only caused minor injuries to the deceased. This can prove to a certain extent that he was not very strong, a weak woman, or an immature child. minor."
"Third, the murderer still chose to break in and attack even though the lights were on, which shows that he is extremely courageous, impulsive and reckless, which is also consistent with the psychological characteristics of a juvenile murderer."
"Finally, the direction of the path proves that the murderer's murderous movement was a 'downward stabbing', and when the murderer stabbed the deceased with a knife, he hit the upper right abdomen."
"And if you are an adult of normal height, hold the knife high and stab it downwards."
Lin Xinyi tried to raise the knife over his shoulder in front of Officer Feng Jian.
Since he was much taller than the average adult, if he plunged face to face into the target in this way, the blade would only hit his neck and shoulders.
If it were a shorter adult, it would only hit the chest.
"But the murderer stabbed him further down in his abdomen."
"This shows that compared to the deceased, Mr. Yamazaki, the murderer was much shorter."
"Mr. Yamazaki himself is not too tall. If the murderer is much shorter, then he can only be a minor."
Having said this, Lin Xinyi's face turned a little ugly.
But he still left some hope for himself:
"Of course, because the positions of both parties during the fight cannot be determined, it is not rigorous to judge the height of the murderer just from the location of the wound."
"So, I have to do more detailed and scientific investigations on site."
"If you're lucky, maybe you can overturn my idea."
"This" Officer Feng Jian was stunned for a while: "Then what if the investigation turns out that the murderer is really a minor?"
"." There was silence for a while.
Fang Guling also turned his attention to Lin Xinyi, seeming to be expecting the famous police officer's answer.
"We are police, law enforcers."
Lin Xinyi sighed with a lonely look:
"Follow the law."
The personnel and equipment of the forensics department were quickly sent to the scene.
Lin Xinyi put on a hair cover, shoe covers, mask, and protective clothing, and carefully stepped into the scene.
Before he went deep into the living room area where the crime occurred, he stopped at the entrance, pointed at the open security door of the villa and asked:
"Who opened the door of this villa?"
"I don't know." Officer Feng Jian shook his head: "This door is always open."
"When the police arrived at the scene in the early morning, this was what the scene looked like."
"This" Lin Xinyi frowned slightly.
He didn't say anything, he just looked at the intact security door for a moment, then carried a large survey box and entered the villa.
Then, he was not busy surveying the scene carefully, but walked straight into the blood-stained kitchen.
This was the place where the fatal stabbing was struck.
Rei Fukiya and Yu Kazami followed curiously. They both wanted to see what magic weapon was in the box of the forest administrator.
Then
I saw Lin Xinyi taking out a ruler, pencil, eraser, calculation paper, and calculator.
"This" the well-informed Mr. Fangtani couldn't understand: "Mr. Lin, are you trying to do math problems?"
"Just doing math problems."
Lin Xinyi nodded seriously.
He pointed to a splatter of blood on the wall next to the body of the deceased and said:
"This is the splatter-like blood stain formed by the rupture of human arteries and blood vessels. Splash-like blood stains often indicate the first scene, that is, the starting point of the injury."
"If you find the splattered blood, you can probably find the location of the moment the deceased was stabbed."
"The autopsy report mentioned that there were obvious mobile wounds inside the wound of the deceased, and the skin on the surface of the wound also had the characteristics of being pulled greatly upward."
"So it can be roughly judged that the moment the murderer drew the knife, the body of the deceased was still 'moving' downward."
"In other words, after the murderer stabbed the deceased with a knife, he immediately pulled out the knife."
"And the blood in the deceased's body spewed out in large quantities at this time."
"So as long as we can confirm the 'height' of the blood splatter point, we can indirectly confirm the body position of the deceased when he was stabbed, and thus determine the approximate height of the murderer."
"Well" Jiang Gu and Fengjian were confused when they heard:
"The height of the blood splash point. How to confirm this?"
"By doing math problems."
As Lin Xinyi spoke, he held a ruler and carefully measured the length and width of those splatter-like blood drops:
"Blood droplets contact the object to form traces. If the surface of the object is smooth and flat, the shape of the blood trace will be either circular or oval."
"In other words, the overall shape of the drop-shaped blood stain is oval."
"One side of the oval is smooth and is called the 'head'."
"A small tail-like mark will form on the other side, which is called a 'tail'."
“Based on the shape of the drop-like blood stain, the angle at which the blood drop contacts the object can be judged.”
"The greater the distance difference between the long side and the wide side of the ellipse, the smaller the angle at which the blood droplet contacts the object."
"Oh" Fang Gu Ling nodded thoughtfully: "So that's it, I understand."
Feng Jian: "???"
What do you understand?
Why don't I understand?
He still looked confused.
Jianggu Ling smiled softly:
"What Mr. Lin means is to first measure the ratio of the minor axis and the major axis of the ellipse, and then determine the incident angle corresponding to the ratio based on the sine function."
"Actually, it's just junior high school math."
"Kazemi, if you remember the ballistic calculation method taught in the sniper class, you can easily understand this knowledge."
"Can you still use a sniper rifle?"
Lin Xinyi interjected curiously.
"This is our public security training course." Fangtani Rei replied noncommittally.
"Well."
Lin Xinyi handed him paper, pen, and calculator unceremoniously:
"I'll measure it, you'll do the math, and we'll speed up the work."
An agent who can even calculate the trajectory of a sniper shot will not be able to make mistakes on a calculator.
So he safely handed over the arithmetic work to Jianggu Ling, and casually said:
"Don't make a mistake."
"The measurement and calculation of each blood drop must be accurate, otherwise the final error will be quite terrible."
With that said, Lin Xinyi continued to work hard.
This work is very tedious:
He had to first select an area where blood stains were concentrated, then measure the length and width of each blood droplet in the concentrated area, and then calculate the incident angle of each blood droplet.
Confirm the direction according to the "head and tail" of the oval blood drop, and then use the "pulling wire method" to position it based on the directionality and incident angle of the blood stain.
That is, a section of the line is fixed at the end of the bloodstain, and the fixed point is located at the endpoint of the long axis of the bloodstain away from the tail of the bloodstain.
Then extend the line in the opposite direction along the calculated direction and angle.
Finally, the intersection of several extended bloodstain lines above the plane is the location of the bleeding point.
This work is very detailed and tedious, prone to errors, and the operation of pulling up multiple lines is also extremely complicated.
Its operation is so difficult that even the weird murderers in this world who have eaten the "Thread Fruit" will have to surrender.
If it is in the future, the "computer programming method" can be used to replace this cumbersome "wire pulling method"——
You only need to take a digital camera to take a picture of the blood stains at the scene, and then put the photo into the blood stain analysis program to get the results quickly.
But in this day and age, mobile phones are still Nokia, and this is the only method Lin Xinyi can use.
Only with the utmost care and effort can we find the location of the bleeding point relatively accurately.
Lin Xinyi just kept busy.
He carefully squatted in front of the bloodstain, carefully measuring, calculating, and pulling the thread. Even though his forehead was covered with sweat, he refused to relax and rest.
Finally, the results came out.
"Calculate the height of the bleeding point, combine it with the angle of the knife and the height of the deceased to determine the height of the murderer."
Lin Xinyi felt helpless at this result:
"Maybe not even 1.5 meters."
"I'm afraid, this guy is just a junior high school student."
"This junior high school student?"
If you are a junior high school student, you must be under 16 years old.
Kazami Yuya still wanted to escape this answer:
"Mr. Lin, could the murderer be...congenitally stunted?"
"You mean the dwarf?"
"It's not impossible."
Lin Xinyi sighed deeply and his tone became more complicated:
"But think about it if you're an adult and you know you're small and don't have much strength."
"How dare you break into someone's home with a hammer and attack an able-bodied adult male?"
Officer Feng Jian was speechless:
Indeed, the murderer was not only short in stature, but also had an eccentric temperament.
What's even scarier is.
"The murderer has such confidence, not only because he is young and impulsive, but also because he knows that he is a minor:"
"He knows that even if he breaks into a house with a weapon and kills people, he will succeed or fail."
"No one else can do anything to him."
The second is later