National Forensic Doctor

80: Chapter 79 Serene Atmosphere 80: Chapter 79 Serene Atmosphere Afternoon.

Sunlight scattered across the courtyard, creating a peaceful atmosphere.

There were only six detectives, all working diligently to send seven individuals and even more to prison.

“Magnetic powder will do.”

“Let’s start with the ultraviolet light first.”

“For this…

ninhydrin.”

Jiang Yuan had been at the crime scene for several hours and easily gained authority over the scene.

In the beginning, a few were not quite used to his style, but gradually, they became familiar with Jiang Yuan’s way of working.

At that moment, the crime scene resembled a workshop or an office where the presence of a highly skilled technician eventually directed everyone toward the same or similar technical standards; otherwise, work could not proceed.

In terms of fingerprints alone, those that the crime scene investigators from Ningtai County collected were to be processed by Yan Ge and Wang Zhong.

Their requirements were simply clarity and accuracy—if they didn’t succeed, there wouldn’t be much discussion, just an acceptance of their own shortcomings.

However, Jiang Yuan’s demands in this area were quite different, because he knew what he could achieve.

Therefore, his demands for fingerprints to be compared and processed into the database were naturally much higher.

Most importantly, Jiang Yuan was able to provide clear methods to obtain the distinct fingerprints.

Many scene investigators, since leaving school, had truly never enjoyed such “instruction.”

Ninhydrin for fingerprint visualization, for example, is supposed to be the most commonly used technique—both in textbooks, classrooms, and many crime scenes.

It’s a chemical reaction, quite complex in nature, but as for the results, ninhydrin is capable of clearly revealing latent fingerprints on light-colored paper, tickets, and even wooden items.

It’s an extremely effective and extraordinary solution.

But in actual crime scene investigations, detectives rarely use this method.

It’s no exaggeration to say that for the majority of crime scene investigations, the most commonly used, or even the only used method, is powder dusting.

“One brush sweeps across the world” is the daily reality for most crime scene investigators.

They don’t even bother changing the type of powder.

Today’s crime scene investigators are technicians from the criminal investigation team.

Under very rare circumstances, they would use ninhydrin and super glue fuming.

Today, with the entire team mobilized, so many technicians came out.

Normally, for many minor cases, the responding detectives and station officers would scan fingerprints at the scene and enter them into the database, and many of them don’t really know how to use ninhydrin or super glue fuming.

In fact, because of its rarity of use, the technicians from the criminal investigation team are not very proficient with ninhydrin and super glue fuming.

This is easily understandable—if a person takes the same route to work every day and can arrive smoothly, unless there’s an unexpected situation and the usual route is completely blocked, why would they change paths?

The technicians from Ningtai County are like this; if fingerprints can be revealed with powder, they certainly will be revealed with powder.

They don’t even bother changing the type of the powder.

Only if the surface is not smooth, like on textiles, where fingerprints cannot be revealed with powder, and only if the fingerprints are important, would a technician consider using ninhydrin.

It’s like sticking to the usual path unless severe weather conditions destroy the road or an unexpected event causes a traffic jam.

Nevertheless, the ones who previously analyzed fingerprints were Yan Ge and Wang Zhong, but now it’s Jiang Yuan.

Jiang Yuan is like an employer demanding on-time arrival and constantly seeking to reduce commuting time.

It became very important for the technicians at the scene to choose the right method if they wanted to meet this standard.

Of course, what’s important is that they are also willing to reduce commuting time or, in other words, are willing to cooperate with Jiang Yuan to improve the quality of fingerprints entered into the database.

In forensic science and technology, this is akin to a martial arts secret manual—it’s both a means to secure a livelihood and a tool for self-improvement.

People generally prefer to do things well.

And doing anything well is always a bit difficult.

Take ninhydrin: anyone who’s studied three or four years at a police academy can boldly claim, “I’m familiar with this.”

But when you actually ask, “Which kind of ninhydrin formula do you usually use?” eighty percent would be stumped.

Only someone like Wang Zhong, who has truly used ninhydrin, could easily whip up a formula with 1g of ninhydrin and 100g of anhydrous ethanol, adding, “We used to use acetone more, but it’s strictly regulated now, and it’s not easy to get a lot of it…”

Jiang Yuan responded unforgivingly, “I suggest adding ether.”

“Oh, a formula with ether?

Add…

60g?” Wang Zhong pondered the formula, clearly not very sure of it.

Jiang Yuandao said, “You need 2g of ninhydrin, then add 33.5g of anhydrous ethanol, followed by 66.5g of ether.

Since the latent fingerprint we are working on is on a gluey substance, adding ether will make it significantly clearer.

The one-to-one hundred ethanol formula you were just using works fine on paper, but it won’t be effective on gluey substances.”

“I can’t believe it slipped my mind, I’ve learned this formula before.” Wang Zhong smacked his forehead.

He had learned it, but after several years of use, he simply couldn’t recall the formula.

Wang Zhong then prepared the ninhydrin solution on-the-spot and applied it to a kraft paper bag.

Jiang Yuan moved his lips but did not make any further requests.

The color development time for ninhydrin is one to two hours, but there are other methods to speed up the process.

However, since there was still plenty of time, Jiang Yuan saw no need to be nitpicky.

With no further questions asked, Jiang Yuan proceeded to work on non-smooth surfaces on his own.

Detectives typically look for fingerprints on smooth surfaces.

Or to put it another way, based on their skill level, if they can clarify fingerprints on smooth surfaces, it’s already no small feat.

Jiang Yuan then took a glue gun out of the crime scene kit.

He sprinkled powder on the LV monogrammed leather bag from which he wanted to lift fingerprints, then raised the glue gun and sprayed a thick, gluey substance, using a blow dryer to apply heat.

The nearby crime scene investigators were stunned.

“Do we even have this equipment?” A crime scene investigator wondered, filled with questions.

“Found it in the storage,” said Jiang Yuan, holding the glue gun.

He began to stride around, adding, “I guess it was bought as a complete set.”

“Certainly, nowadays everything is packaged…” The investigators watched with a sense of helplessness, suddenly feeling completely unaware of the bureau’s resources.