Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

Chapter 62 Extracting Fingerprints
The identification and analysis of fingerprints should be said to start from fingerprint collection.

The quality of collected fingerprints fundamentally determines the difficulty and success probability of fingerprint identification and analysis.

Lu Chuan has already collected the fingerprints on the frame.

This time, Lu Chuan did not use ordinary silver powder or rarely used copper powder, but collected it by magnetic adhesion.

This is because the material of the picture frame is a composite board pressed by crushed wood, and then painted.

Compared with several commonly used fingerprint collection methods, magnetically adhering fingerprints on the surface of this carrier has the best effect and least damage to fingerprints.

At the same time, due to the twisting of fingers during the handling process, many fingerprints on the frame are scratched.

This kind of fingerprint collection is also suitable for the method of magnetic adhesion.

"Master, the fingerprints on the picture frame are mixed. During the back and forth transportation, there must be many people's fingerprints. It is hard to say whether there are fingerprints of criminal suspects in it."

Liu Guodong nodded.

I just heard the news from the action group that the artist who signed the painting has been found, but the other party said that he had never painted this girl in the wheat waves.

Therefore, it is impossible to determine who the murderer is at present.

"The focus now is on the fingerprints on the paint and the fingerprints on the skin. This time you will do the surgery. If we need our cooperation, you will arrange it."

Lu Chuan nodded: "I'll try first, there are still some things, I need to communicate with Shen Yan."

Lu Chuan has a way to collect fingerprints on the paint, but for fingerprints that may exist on the skin, there is a high probability that the resin paint on it needs to be destroyed.

This has effects on the skin itself, which naturally requires the consent of a forensic medical examiner.

In the laboratory, Lu Chuan turned off all the lamps and used an ultraviolet portable lamp to observe the paint inch by inch.

Oil painting is different from traditional Chinese painting. The pigment itself has a grainy feel. In the process of painting, the painter can also use lines of different shades to reflect the change of space.

Therefore, the oil painting looks more realistic, the contrast between light and dark is stronger, and the sense of space is stronger.

However, this is not a good thing for fingerprint collection.

The wheat waves in the picture seem to be really dancing with the wind.

Between the ups and downs, Lu Chuan has already found some fingerprints.

However, there are so many breakpoints in these fingerprints that basically every line has a breakpoint.

In addition, the pigments in this oil painting are minerals, which themselves contain sodium, iron, copper and other elements.

Therefore, in this case, ordinary physical and chemical methods will fail.

This time, Lu Chuan still needs to use a frequency conversion laser spectrum analyzer to develop fingerprints.

However, unlike developing fingerprints on paper, on oil paintings, the laser wavelength required for development is variable.

Fortunately, in the intermediate fingerprint collection skills, there is a reserve of experience in this area.

Lu Chuan only needs to constantly adjust the wavelength to develop fingerprints on different pigments, and then piece together each developed fingerprint through photos to complete the collection.

In the dark laboratory, Lu Chuan was constantly adjusting the laser frequency of the instrument, and sections of fingerprints kept flashing.

Liu Guodong cooperated with the camera to record each segment of fingerprints.

While Lu Chuan was extracting the fingerprints on the paint, the inquiry of the second operation group was also going on.

However, the effect is far from ideal.

Zhang Bin, the person in charge of the exhibition hall.

"I really don't know how this painting came to be."

"You have also read the specific information just now. The artist is Liang Song, a local grassroots painter in Haizhou. You should ask him."

The person in charge of exhibition hall arrangement.

"These paintings are all donated. Except for a few more expensive paintings that are loaned out, the rest are either actively contacted by the artist or invited by us to be exhibited in the exhibition hall."

"You don't have any review mechanism for your exhibition paintings?"

"There are, but there are not many painters in Haizhou, and there are even fewer excellent paintings. As long as they are similar, we will put them in the exhibition."

"The level of this literary and art exhibition is not high. Although Liang Song is a grassroots painter, he is actually quite famous in Haizhou City."

"Then how did this painting enter the exhibition hall? Who carried it? Where did it come from?"

"On Thursday, the exhibition was completed the day before yesterday. We have a professional moving team. We sent people to move the paintings directly to Mr. Liang Song's studio..."

The action group is responsible for interrogating the room.

Liang Song is a man in his 50s with a moustache. He has the temperament of an artistic uncle. At the moment in the inquiry room, there is no nervousness or fear in his eyes like ordinary people.

Sun Jun could see that Liang Song seemed to be curious, and kept looking at everything around him.

"Mr. Liang, you don't seem nervous at all?"

Liang Song stopped looking and looked at Sun Jun: "Why should I be nervous?"

"After entering this place, there are not many people who are not nervous."

"That's because they committed a crime. I didn't commit a crime. Of course I'm not nervous, but..."

Liang Song changed his tone: "I can make a painting based on my experience of inquiry when I go back. It's called...it's called freedom. What do you think?"

free?

Sun Jun said dumbly: "Mr. Liang, I think it's better to call it loss of freedom."

"Okay, let's talk about your painting."

Liang Song shook his head: "I told you in the car that I didn't draw that painting."

"Although I often draw wheat waves and some works with rural themes, the girl in the wheat waves you mentioned is really not my painting."

"But the painting is signed by you, and according to the people in the exhibition venue, this painting was shipped out of your studio."

Liang Song frowned deeply: "Officer Sun, I really don't know what's going on."

"I know about this art exhibition, they sent me an invitation letter."

"I also agreed to show them my paintings, and honestly, I want them to show mine too."

"As a grassroots painter, I don't have a teacher, and I paint by myself."

"So, I cherish this exhibition opportunity."

"Besides, I knew from the photo of the painting you showed me in the car that Mai Lang's painting was really good, but the painting was really not mine."

"The painting I provided to them was called The Dry Well by the Wheat Field."

"On the reply letter to the exhibition hall, there is the name of the painting."

"If you don't believe me, you can go to my studio to have a look. If something goes wrong, the painting of the dry well next to the wheat field should still be in my studio."

"Also... As for whether this painting was painted by me, you can also ask some well-known painters to identify it. It's not very difficult..."

28:[-] p.m.

In conference room No. [-], Qin Yong presided over the first case analysis meeting.

"The action team, the current survey, and the forensic doctor all talked about it. What's the progress now?"

(End of this chapter)