The tape extraction method is suitable for extracting dust fingerprints on smooth object surfaces.

When the contrast between the dust fingerprint and the object is not obvious like now, using tape to stick it on can avoid the influence of the object.

At Lin Xinyi's request, the Seha family's servant quickly delivered a roll of wide tape.

The Seyu family has a large business, and the utility room is wider than the living room of an ordinary family. All kinds of daily necessities are always ready.

So, in the nervous eyes of Mr. Seyu...

Lin Xinyi first used his own tape to extract the fingerprints he left.

The extraction process is also very simple...

The principle and operation are probably similar to the way elementary school students use tape to remove typos in their homework books.

Spread the wide tape evenly on the glass, press it firmly, and then carefully peel it off.

The fingerprint made of dust was completely stuck to the wide tape.

"But... you still can't see clearly?"

The police officers asked with concern.

Although the fingerprints printed on the tape are convenient to hold, they are still a bit unclear.

"It's okay, have you forgotten what you did to find the fingerprints just now?"

"We can also use this light transmission enhancement method, and it is more convenient to operate."

As he spoke, Lin Xinyi gently placed the wide tape with fingerprints on it in front of the black body of the TV in the guest room.

When the background color is changed, the contrast becomes more obvious.

The fingerprints on the tape suddenly became much clearer.

"Here, flashlight, then use a 45-degree angle to light it from the side."

Lin Xinyi continued to guide several rookie operations:

But this time when the lights were turned on, the dust fingerprints on the wide tape appeared more clearly against the black background.

Because of the particle nature of dust, dust fingerprints are opaque and diffusely reflective, while the tape used to capture dust fingerprints has better light transmittance.

Therefore, when the light source is irradiated at a 45-degree angle, the part of the tape with dust attached will be in a diffuse reflection state under the light, and the part of the tape without dust will be in a specular reflection state under the light, thus effectively strengthening the fingerprint.

Contrast.

"Now we can see clearly!" the police officers from the forensics department shouted excitedly.

"Take photos and record them." Lin Xinyi calmly ordered them to do the only thing they were good at.

In this way, the police officers from the Forensic Division took photos of the fingerprints and recorded them, and the wide tape with the fingerprints on them was well preserved.

"This this..."

Seba Tundoku's face changed slightly, and then he pretended to be calm and asked:

"With this handprint, we can catch the criminal, right?"

"It can make a big difference."

"Because age, gender, weight, bones and other factors vary, the outline of each person's hand will be slightly different."

"Although there is no palmprint that can accurately lock the identity, by comparing the outline of the hand, at least the scope of the investigation can be greatly reduced."

Lin Xinyi explained it carefully using words like this.

"Oh... I'm just narrowing it down..."

Mr. Seba's tortured heart was able to breathe again.

But he didn't expect that Lin Xinyi was like the master of Landlords who had 17 cards in his hand. Although he had thrown the bomb, the good cards in his hand were far from finished:

"It's still a bit difficult to find the murderer based on fingerprints."

"So I will use another method to extract the murderer's footprints."

"Footprints?"

Several forensic police officers asked curiously:

"Wide tape can still detect and extract footprints?"

"No, we can't use tape this time." Lin Xinyi shook his head slightly:

The adhesive tape is so strong that it can absorb almost all the dust on the object surface.

The glass window was cleaned every day by the servants. It was originally clean and there was no dust.

All dust fingerprints can be extracted from the glass directly with tape without being interfered by other dust.

But the footprints are different.

Footprints may be on the floor, walls and marble handrails...

Those places are rougher than the glass and covered with more dust.

If you directly use a highly adhesive tape to stick it, you may end up with only a piece of tape covered with dust.

Therefore, if you want to extract footprints, you must use a more technological method.

"that..."

Lin Xinyi looked around in the guest room.

Finally, he stared at the square, old-fashioned TV set:

"Tear this TV apart and remove the black chassis panel from the side of the TV."

"Eh?" None of the police officers responded:

Why dismantle someone else’s TV when the TV can also be used to solve crimes?

"Just tear it down!"

"If you destroy me...well...the Mumu Police Department will pay for it!"

Lin Xinyi urged without explanation.

So, several young police officers quickly and quickly dismantled the TV.

Seha Tatsunoku wanted to stop it very much, but he couldn't speak out - as a chaebol boss, it was impossible for him to be reluctant to part with a TV.

Soon, the television was disemboweled.

The flat and wide black fuselage side panel was also carefully removed by the police officers.

"Then what?"

Looking at this big black plastic plate, everyone was confused.

But Lin Xinyi pointed at the plastic plate that had just been removed from the TV and ordered the police officers:

"You take a few pieces of clothing or other textiles and rub them against this plastic plate."

"Friction?" The police officers were slightly startled.

"friction!"

Lin Xinyi felt like he was teaching primary school students.

And if you think about it carefully... breathing, lighting, and adding tape... what he taught seems to be all things that elementary school students know.

Even the trick being used now is within the knowledge of primary school students:

"Friction generates electricity, understand?"

"Use friction to make the plastic board static, and then spread the static plastic board to places where dust footprints may remain."

As a forensic doctor, Lin Xinyi will appear at the scene every time with his colleagues who are also technical investigators.

The equipment they use most to extract dust footprints is the electrostatic adsorber.

There are no ready-made electrostatic adsorbers now, so Lin Xinyi can only try to let these police officers use local methods and materials to create an electrostatic adsorption device through human friction.

“When a small non-static object is close to a static-charged object, due to the phenomenon of electrostatic induction, the end close to the static-charged object will induce an electric property opposite to that of the static-charged object, which will cause the tiny object to be attracted and attached to the electrostatic-charged object.

on objects.”

Lin Xinyi briefly explained the principle of electrostatic adsorption:

"So as long as you lay the electrostatically charged plastic board where there may be dust footprints, the dust on the object will be adsorbed to the plastic board due to the electrostatic adsorption effect."

"The dust on the object is transferred to the black plastic plate. Because the background color difference is enhanced, the dust footprints that were originally difficult to distinguish with the naked eye can appear relatively clearly."

He explained at length.

I don’t know if the police officers understood it, but they were busy in full swing anyway.

A few young men took off their coats and rubbed hard against this black plastic board. After a while, the board almost started to burn.

Then, following Lin Xinyi's instructions, they tried to spread the plastic sheets that had been charged with static electricity on the balcony guardrail handrails.

This guardrail handrail is made of marble and has a relatively wide upper edge, which is very suitable for using your feet when climbing.
To be continued...