Coroner Coroner

Therefore, it has been subtle these days that whenever encountering difficult and miscellaneous cases, everyone will immediately think of this invincible manager Lin.

"Eh..." Lin Xinyi's expression was a little bit embarrassed.

He had just heard the report from Sato Miwako about the general incident.

Generally speaking, cases where the murderer didn't run away after killing someone and stayed on the scene pretending to be innocent are very easy to solve.

There is no need for anyone to think of a way, let Caesar go out and catch one at a time.

But this murderer was not ordinary.

"The work clothes he wore when he committed the crime were almost burned."

"The pistol left at the scene can't help but be wiped clean, and it has also been roasted, so that there will be no smell of the murderer."

"And the ground of this entire floor is still covered by stagnant water, and the footprints and smell left by the murderer also disappear."

"And Ms. Mori and Ms. Sato haven't seen the real face of the murderer yet, so they don't know what he looks like..."

"To be honest, it is difficult to find him among so many people."

Lin Xinyi reluctantly stated the difficulties he encountered.

There was only one old man in a suit and leather shoes in the crowd who was secretly relieved.

Others, especially the colleagues in the Metropolitan Police Department, don't have such good-looking expressions:

"Then what to do, Manager Lin?"

"..."

Lin Xinyi sighed helplessly:

He complained about this suffering in order to let everyone work together to find a way and help put forward opinions.

The result was a piece of innocent big eyes of Teletubbies.

Among the elites of the Metropolitan Police Department present, it was obvious that no one could help him.

He can only try his luck:

"I'll go to the scene to see first..."

"Let the forensics class bring all the personnel and equipment over, the more complete the better."

"By the way, don't forget to bring Caesar."

At this critical juncture, it is the only reliable one among colleagues.

Lin Xinyi made some simple arrangements, and then brought Mao Lilan and Sato Miwako, who had personally experienced the case, back to the scene to start a preliminary investigation.

The first thing I went to was the women's bathroom.

"Damn...the bathroom also has fire sprinklers?"

Lin Xinyi was defeated by Mihua Hotel's high standard security configuration:

There was more water on the floor of the bathroom than in the corridor outside, and the remaining footprints and smells on the floor were completely destroyed.

As for fingerprints, palm prints, hair, etc...

The murderer was wearing gloves and a hair cover to commit the crime, and these things would never be left at the scene.

And the gloves he wore when he committed the crime, along with his clothes, were burned by him.

"This murderer has a trick!"

"And choose this kind of timing to assassinate Ms. Suzuki..."

"I'm afraid it is a professional killer from an underground organization."

Lin Xinyi secretly lamented the professionalism of the murderer.

In his mind, he suddenly came up with a rich family's grievances that could make 80 episodes of TV series:

Who would invite a killer to assassinate Suzuki Sonoko?

Sonoko Suzuki is dead, who benefits the most?

According to this line of thinking, Suzuki Sonoko's older sister will be turned into an evil young lady who kills her sister and fights for her inheritance.

"Probably not..."

Thinking of that Miss Suzuki Ayako who spoke in a weak voice, Lin Xinyi temporarily dispelled this unreasonable speculation.

In the end, he gave up the reasoning and imagination that he was not good at, and honestly started from the perspective of on-site investigation:

"Let's go to the utility room and have a look."

"If you can't find any traces there, I'm afraid things will be troublesome."

Lin Xinyi sighed lightly, then turned and walked towards the utility room.

And just as he walked to the door of the utility room, he just looked in at the narrow space structure of the utility room, and his expression suddenly changed:

"This... close the door quickly!"

"Don't let the air inside escape!"

"Eh?" Mao Lilan was slightly taken aback.

She subconsciously obeyed Lin Xinyi's order, closed the door of the utility room, and then asked a little puzzled:

"Mr. Lin, have you found any clues?"

"That's right...the air in this room is the clue!" Lin Xinyi replied succinctly: "There is a scent of the murderer in it, which can be used by Caesar to track it down."

"Police dog tracking?"

Hearing the method proposed by Lin Xinyi, Mao Lilan was a little puzzled:

"But there are fire sprinklers in the utility room, too."

"The ground in the utility room is also soaked in stagnant water, and there is no way to extract the residual smell."

"No, it's okay if the ground doesn't smell."

Lin Xinyi shook his head:

Mao Lilan, as well as other trained forensics officers, are used to extracting residual odors from the footprints on the scene.

This is because human feet have the heaviest odor.

Moreover, the soles of the feet are in direct contact with the ground, and the smell can be better attached to the ground and stored for a longer period of time.

If it's on dirt ground, the smell lasts for up to a day under standard windless conditions.

Even on such an indoor hard concrete floor, the smell can still retain 3% of the initial concentration after 10 hours under standard windless conditions.

But all of these, once washed by the water, are all gone.

That's why Mao Lilan felt that in this case, police dog forensics was no longer feasible.

"But it's actually possible."

"Think about it carefully, I taught you that extracting the smell source does not have to go through a solid medium like the ground."

"Under special conditions, we can extract smell sources directly from the air!"

After Lin Xinyi explained, Mao Lilan suddenly realized:

"Oh, right."

"In a narrow and confined space, we can extract the smell directly from the air!"

Following Lin Xinyi's prompt, she carefully recalled the spatial structure of the utility room.

There was very little space in that utility room.

And there are no windows, no vents.

Even with the door open, air and outside circulation is slow.

Although there is a fire sprinkler inside, it has been sprayed with water.

But the shower spray from the fire sprinkler could not cover all the air in this utility room after all.

There is still a large part of the air that has not been washed by the water mist. If there are residual body odor molecules in it, it may still remain in this utility room until now.

"It's not very promising, but it's worth a try."

"As long as there's residual body odor in the collected air...then we'll soon know who the killer is."

All traces that could be investigated were erased by the murderer.

Lin Xin pinned all his hopes on Caesar.

He blocked the door tightly, and even used tape to plug the gaps that might leak air, and then waited for the forensic team to bring Caesar and the equipment to the scene.

And because this slap hit the criminal minister directly, everyone's action speed has obviously improved.

It didn't take long for the hotel to wait, and the equipment and dogs were delivered to the scene.

Caesar was officially on duty this time, wearing the black vest uniform of Olice, sitting there vigorously, looking very majestic.

Lin Xinyi touched its head, and then told his subordinates:

"Bring over the field scent extractor."

Using an on-site odor extractor to extract odors is another odor extraction method that is different from the gauze infection method.

This is also generally used to extract odors from footprints, clothing, gloves, etc.

Generally, the article to extract the smell is put into the airtight gas collecting hood, and then the air is continuously pumped by the suction device.

The gas will be drawn from the gas collection hood to the odor enrichment chamber, through the adsorption device filled with suction cloth or molecular plug.

Probably a "range hood" with a "filter".

Now, Lin Xinyi wants to use it to directly extract the air in the utility room.

In use, it looks a bit like a vacuum cleaner.

It's just that what is sucked is not dust, but the air in this closed utility room.

After a lot of hard work, Lin Xinyi had vigorously pumped the air in the utility room.

If there are body odor molecules left by the prisoners, they should all be concentrated on the inhalation cloth in the odor enrichment chamber at this moment.