The famous detective in the comic world

Chapter 277 Luminol

"Yes, you heard it right." Seeing Tom stop and turn around, He Nan looked at him and sighed: "The phonograph in this case is of a special style, the stylus moves, but the record does not move. Usually It’s the other way around. To perform strangulation, you need a strong power and a high-quality stylus...and during the strangulation process, it is likely to cause the record to play the wrong track due to the misplacement of the stylus scratch. Originally Well, a piece of music that might play here one second and there the next... that sounds very weird, Tom. Of course, it's just possible..."

"You said you can imitate needle strangulation... what do you mean?"

"Because the movement track of the stylus is fixed. It starts circular movement from the groove on the periphery of the record, and then turns to the next circle at the pre-set position after one circle, gradually shrinking. If you want to use it to perform strangulation, you must first use it. Make a set of piano wire around the neck of the deceased, and then tie another section to the needle. By rotating, the throat of the deceased is cut with a sharp piano wire, causing the throat to break. This movement process cannot cut off the head, so it will cause The stylus got stuck—in the end, the dead man's cutting marks extended to one side, and there was only one main point of force in the wound." He Nan said so, and drew a picture for him in his notebook.

Then, he went on to explain: "Usually the stylus rotates clockwise, so the wounds of the deceased were cut open from the right side. The autopsy report also mentioned this. This is why she was determined to be using a phonograph. One of the main reasons for hanging yourself... Another reason is that the room was locked. I will investigate how this is done later on."

"Okay, let's talk about it again - in fact, having someone hold a piano wire and cut it slowly may also have the same effect." He Nan said so, and simply drew a wound analysis diagram of the deceased on the picture: " Considering that the deceased may be struggling, it is more likely that one person will hold her down while the other slowly operates. Considering the bleeding problem...the possibility that the deceased was killed by the phonograph is even greater , To put it bluntly, there is only one scene.”

Tom gritted his teeth as he listened, looking sullen and pale.

He Nan guessed that he was imagining his wife being treated so cruelly, and couldn't help feeling sad.

...Of course, it may also be that he was frightened by the explanatory picture drawn by He Nan.

Realizing this, He Nan put away his notebook and walked into the room: "Come on, let's take a good look at the scene."

He Nan walked into the innermost room in the northwest corner of the second floor.

The moment he entered the room, he could hear Tom sighing heavily.

He Nan couldn't comfort him either, so he had to go inside first and observe the surroundings.

Soon, I saw the gramophone.

The bloodstains had indeed been cleaned away.

...But most likely, it is just cleaned so that it cannot be seen or smelled.

There is no reason for the police to completely wash off the remaining chemical components.That's just costly -- both time and money.

There are no photos of the whole body in the files, only the wounds.

But this is not enough.

He would have to see all the blood in the room to make the most accurate inferences.

So, He Nan drew the curtains, Shirley closed the door knowingly - the room was suddenly plunged into darkness.

"What is this for?" Tom asked in a daze.

"We're going to conduct a luminol test." He Nan took out the luminol reagent and stimulant solution from his pocket in the coat: "This thing can expose bloodstains that are invisible to the naked eye."

Pure luminol is a luminescent chemical reagent, but when mixed with an appropriate oxidant, it can emit blue light, which is enough to see clearly in a dark place.

The bottle in He Nan's hand was a mixture of two liquids.One bottle is split in half with two spray holes in the front and back.

The corresponding solution can be sprayed out by pressing the corresponding button, which is very convenient.This kind of thing is usually used by detectives, and the two solutions are bottled separately for forensics.

This thing is nice to use.

Just spray the luminol reagent on the area where there may be blood, and then spray the activator solution.

If there is blood, urine and other substances, it will react with the iron element in it and emit a faint blue light.Lasts about 30 seconds.

This phenomenon can be observed with the naked eye if the surrounding environment is dark enough.

If the surrounding area is not dark enough, it needs to be photographed first and then observed through long-exposure photos, X-ray film development, fluorescent CCD scanning imaging and other means.

Of course, because the luminous time is too short, it should be photographed anyway.

The situation that He Nan was most worried about, apart from encountering blood in the urine (the phenomenon of luminol reaction is exactly the same), was that the prisoner had used some type of bleach to clean the blood stains.

That's trouble.

Because the luminol reagent will fluoresce strongly when it encounters certain components of bleach (copper, copper-containing alloys, and horseradish also have this reaction), covering up the faint blue light of the bloodstain.

Still, seasoned detectives and forensic scientists can sometimes see the difference.

Because the light of one is continuously shining, and the other is appearing slightly slowly.

But this difference does not exist all the time, and sometimes there is no difference at all.So it would be unwise to assume that there is no trace of blood here.In fact, when encountering this situation, you should be more vigilant.

Because the blood here could be quite critical.

The amount of information it might reveal, such as its shape, may be enough to determine whether the killer will get away with it.

"Okay, it's time to spray..." He Nan turned to look at Xue Li: "Xue Li?"

"Yeah." Shirley took out a Polaroid and nodded, "Let's get started."

It's too tight to do this kind of thing by yourself.

It is better to spray alone, and take pictures alone.

Moreover, ordinary cameras cannot be used at this time.

A Polaroid with a memory card is the best choice - the quality should not be too bad, once the resolution is not high enough, it may affect the effect of careful observation.

In addition to carefully viewing the photo with a magnifying glass, it must be able to withstand zoom review.

No one wants their case to be lost in such a matter.Money that should not be saved must not be saved.

Hey, it's just a bit expensive... He Nan secretly complained about the photo cost of this Polaroid camera: it costs five dollars to take a picture.

Alright, come here now...

He Nan walked to the place where the dead body was at that time, and sprayed the luminol reagent.

Whether it's the phonograph, the seats, the floor, the chairs... or the surrounding curtains, they were all sprayed with luminol by Ho Nan.

Then, He Nan looked at Shirley, saw that she nodded, and quickly sprayed the activator on all the areas where the solution had just been sprayed with a serious expression.

(End of this chapter)