The police found no blood residue in the bathroom, and the luminol test, which had always been effective, was ineffective.
Even the detergent was washed away completely.
How much water do prisoners actually use?
Makoto Sakaki once said that if there is a criminal who can perfectly clean up the blood traces at the crime scene, then he must be a born criminal or a top chemist.
Only prisoners who truly understand the working principle of luminol reagent can find a way to avoid reagent detection.
"This place must have been scrubbed!"
Conan grabbed his hair in annoyance:
"How come there are no traces?"
“This is the bathroom.”
Glancing at him, Sakaki Cheng said calmly:
"What better place to clean up than the bathroom?"
"If the prisoner wants, he can use several tons of water to wash away the blood on the ground."
"The amount of luminol that can be detected is only one part per million! There should be some trace left behind!"
Everyone's faces were very unhappy. They could roughly guess that the criminal had used some method to completely remove the blood residue, but...
They didn't know what methods the other party used.
Mere speculation cannot be used as evidence.
Conan hated this feeling. For the first time, he felt like he had lost, lost at the thing he was best at. The criminal was like a night watchman fiddling with a maze, and he was a little lamb who had strayed into the maze, looking at the walls that kept moving around him, trembling in fear, and in a constant state of panic.
Unraveling the mystery of the criminal seems to be an important factor in breaking the deadlock.
"Two great detectives, please say something!"
Ishimoto Kyokichi shouted:
"You have captured so many criminals, do you have to be trapped in Hakone?"
Kogoro Mori lit a cigarette and said nothing. His eyes were hidden in the smoke, as if he wanted to see through the secret hidden behind the smoke.
As for Sakaki Makoto...
Rubbing his eyebrows, he felt a little headache.
To be honest, he had encountered powerful criminals before, but a criminal who could clean up the blood traces at the scene would not need to resort to such bizarre means as killing and hanging the corpse, as if he was taking revenge on Naoki Kiyomizu.
"have no idea...."
Just when everyone was at a loss, Miss Miyano, who was standing alone, suddenly spoke in a cold voice:
"Have you ever heard of disodium EDTA?"
"Disodium EDTA?"
Sakaki Makoto raised his eyebrows:
“Isn’t this an industrial chelating agent?”
"Yes, the chemical formula of disodium EDTA is C10H14N2Na2O8. It is a very important compound used to chelate a variety of metal ions in hard water, including but not limited to calcium, magnesium, iron, lead, iron, and copper ions."
The corners of her mouth turned up. This was the area where Miss Miyano was best at. Her talent was not just in developing APTX4869:
"Chelation refers to the process of coordination and ring formation between two or more coordinating atoms in the same ligand and the same central atom. Just like a crab's claws clamping food, metal ions such as calcium, magnesium, and iron will be forcibly changed and replaced from their original structure under the action of chelates."
"What does this have to do with luminol?"
Ishimoto Kyoukichi said doubtfully:
"Could it be that disodium EDTA can destroy the blood structure and thus avoid detection by the luminol reagent?"
“It can be done if it’s used in the right way.”
Turning on the bathroom light, everyone's eyes focused on Miss Miyano. She folded her arms and uttered an easy-to-understand explanation from her cherry red lips:
"Many people only know that luminol reagent can detect blood traces, even after decades, but they don't know the luminescence principle of luminol reagent."
"The luminescence of the luminol reagent comes from oxidation, and human blood contains hemoglobin. Hemoglobin is a special protein that transports oxygen in red blood cells. It is composed of globin and heme. Each heme is composed of 4 pyrrole subunits to form a ring with a ferrous ion at the center of the ring. Iron can catalyze the decomposition of hydrogen peroxide (hydrogen peroxide), turning hydrogen peroxide into water and single oxygen, which in turn makes luminol luminescent, so..."
"The luminol reagent is essentially detecting heme left behind at the crime scene."
"oh!"
Slapping his thigh, Ishimoto Kyokichi seemed to understand a little:
"So the luminol reagent needs to be mixed with hydrogen peroxide and luminol solid and prepared on site. Otherwise, over time, the chemically unstable hydrogen peroxide will decompose on its own!"
"That's right."
Nodding, Miss Miyano continued:
"As I said earlier, disodium EDTA, as a chelating agent, can chelate a variety of metal ions in hard water, including ferrous ions."
"According to the steps, as long as the prisoner first uses common 84 disinfectant mixed with water to clean the blood, it can cover the traces in a short time and destroy DNA and other blood proteins, causing hemoglobin to decompose and produce hemolysis, but hemoglobin still exists."
"After hemoglobin is broken down and heme is exposed, it is necessary to wash the ground with a 1:1 EDTA disodium concentrated solution to chelate all metal ions in the blood. The overbearing EDTA disodium concentrated solution will forcibly tear open the heme ring and take away the ferrous ions in the center."
"After this step, use a dilute solution of disodium EDTA for a second cleaning to completely remove all residues. Finally, flush the ground with a large amount of clean water to complete the destruction of evidence."
"Now..."
Miss Miyano glanced at everyone:
My dear, there is more to this chapter. Please click on the next page to continue reading. It’s even more exciting later!
Continue read on readnovelmtl.com
